In their 30 years of making theatre together at The Necessary Stage (TNS), have playwright Haresh Sharma and director Alvin Tan ever had a big fight?

Sharma, 52, says: "We don't fight. We may have disagreements about work or about productions, for example, in rehearsals. We usually settle it by giving each other space. And time. And food."

"Ditto," says Tan, 53.

Space and time and food for thought are what TNS has provided audiences and aspiring theatre- makers since the theatre troupe was registered in 1987.

In recognition of this, both founders have received the Cultural Medallion, Singapore's highest artistic honour - Tan in 2014 and Sharma a year later.

TNS' outreach and impact outstrips its size - the company has only nine full-time employees.

It manages the annual M1 Singapore Fringe Festival, a showcase of edgy performance art that this year provoked censors, but played to packed halls.

It runs a theatre training programme for individuals aged 50 and older; and The Orange Playground, where artists, emerging or established, are invited to "jam" and brainstorm with the troupe. New work from this initiative will be staged for the first time in August, under The Orange Production umbrella.

Such collaboration is traditional for TNS. Today, the troupe is known for plays written by Sharma, with the collaboration of Tan and perhaps the cast, but in the past, it mentored and employed those who form today's who's who list of directors and playwrights.

Kok Heng Leun of Mandarin theatre troupe Drama Box was formerly TNS' business manager. Playwright-director Chong Tze Chien of The Finger Players was a resident playwright at TNS until 2004.

Natalie Hennedige, founder of Cake Theatrical Productions, wrote, acted and directed for TNS. She calls Tan and Sharma her "artistic parents" and has been invited to devise and direct a new work, Being Haresh Sharma, as part of the troupe's 30th anniversary calendar.

As part of the celebrations, TNS will also publish its archives online in June. Theatregoers will be able to revisit or take a first look at those works which changed the perception and impact of Singapore theatre.

Take, for example, the 1999 Completely With/Out Character, performed and devised by the late Paddy Chew with Sharma and Tan. It was the first time anyone spoke publicly and honestly about living with HIV in Singapore.

Off Centre, a stark play about mental illness, lost official funding before its first staging in 1993. In 2007, it became the first Singaporean play to be offered as an O-level text.

TNS works are so important to the local theatre canon that this year, the Esplanade is devoting a season to them. Five theatre practitioners have been asked to respond to plays written by Sharma for the annual showcase of experimental art, The Studios, which runs from March to April.

It is the first time The Studios is focusing on a single playwright, though the programme booklet notes that these plays are devised in collaboration with Tan and after extensive research and dialogue with others.

Nelson Chia, 45-year-old founder of Nine Years Theatre, translates and directs a Mandarin version of Fundamentally Happy for The Studios. He says: "It's so difficult to sum up TNS' contribution in one statement. Community work, education, outreach, working with young people, the Fringe Festival. In Alvin's and Haresh's own work, there is this relentless pushing at boundaries. They have made new playgrounds for us."

Back in the 1980s, there were no such playgrounds for local theatre- makers. Audiences expected local works to be amateurish. Few sponsors invested in theatre groups and local playwrights.

"We are both late starters," Sharma, who is single, says. "There were none of these opportunities that young people have today."

Tan began dabbling in theatre while doing a bachelor's degree in literature and sociology at the National University of Singapore (NUS). He founded a drama group called ! - pronounced silently, but with surprise - in order to stage a Woody Allen play.

Told that the name might put off sponsors, the group was renamed The Necessary Stage. Sharma, who met Tan in NUS, says: "We felt there was so much theatre that could be done. We said we would focus on new works. That's why it was 'The Necessary Stage'."

His first play, Lanterns Never Go Out, about an overworked professional, was written in 1989. A year later, he was the company's first full-time employee and Lanterns Never Go Out was programmed for the Arts Festival. It was a huge risk for the programming team, given opinions about local theatre, but audiences flooded in.

That same year, TNS won more followers with Those Who Can't, Teach, a play about the private lives of teachers.

By 1992, Tan had quit his teaching job at Raffles Institution and the troupe set up as a company, aided by the National Arts Council's (NAC's) theatre-in-residence scheme. They moved into Cairnhill Arts Centre.

Two years later, they nearly closed down. A Straits Times article reported that Tan and Sharma had attended a workshop in New York, conducted by a well-known Brazilian Marxist, Augusto Boal.

In those times, this meant severe consequences. While they were defended by many, including Professor Tommy Koh, then head of NAC, letters went around to schools demanding a boycott of TNS shows.

The shadow eventually passed and, in 2010, Sharma and Tan revisited the experience in the triple-bill - Can Change (pronounced 'blank can change') at the Fringe Festival. The plays were imagined as pieces commissioned by the Government to show that homosexuals could change, single women could start families and Marxists could toe another party line.

It was a straight retelling of all that the troupe had gone through to achieve its current station as an institution of public character - exemplary and with tax benefits for donors. Tan, a bachelor, says: "We weren't parodying anything, but audiences were laughing along."

Keeping it sympathetic, honest and real

TNS has always been part of the system it challenges, creating works that cast a sympathetic, but honest eye on problems such as race relations, road rage and community ties.

In 2000, it moved into its current home at the Marine Parade Community Building and was given a two- year grant of $1 million from NAC.

TNS also started residencies for directors and playwrights, taking on today's 40something-year-old luminaries such as Jeff Chen, Chong and Hennedige.

Chong, 41, had been a child actor in a TNS production at age 12. To actually be a playwright-in-residence was "mind-blowing", he says.

"To me, theatre meant just acting, but what they were trying to achieve was beyond entertainment. Theatre was about humanity, theatre was about making change and being a good example."

Today, his troupe occupies offices in the same building that once housed TNS in the 1990s and he mentors other young playwrights at arts training hub Centre 42.

"It's a legacy we're trying to pass on," he says.

By 2004, TNS' operations were so many and so unwieldy that feedback from NAC - and the artists within the troupe - led to the decision to cut down.

Chong, Hennedige and others left to start their own troupes. Sharma and Tan also moved artistically into minimal-style plays, starting with Fundamentally Happy. The 2006 play about child abuse won multiple prizes at the annual Life Theatre Awards and was adapted into a film shown during the Southeast Asian Film Festival here in 2015.

Coming up next month is Actor, Forty, a monologue devised for Golden Horse Award-winning actress Yeo Yann Yann and commissioned for the Esplanade's Huayi - Chinese Festival of Arts.

Sharma wrote the script, but the dramaturg is Melissa Lim, TNS' general manager. It is her first time in this role. It is unlikely to be her last. TNS is, after all, about renewal, exploration and expansion.

As for the troupe's future? To keep playing and devising new work and eventually plan for the 40th anniversary.

"If you want to know about our future, our Theatre For Seniors programme is it," says Sharma.

Tan nods.

Neither is joking. As they prove, age and a late start have nothing to do with artistry.