When American metal band Metallica play in Singapore on Jan 22 and rock band Guns N' Roses on Feb 25, it'd be all too easy to categorise the stalwarts' concerts as gigs for oldies.
Chances are the most well- received songs at those gigs will be tunes from their landmark albums released 30 years ago.
While both bands have relatively recent songs, what has kept them popular on the touring circuit are the genre-defining music they made from the mid-1980s to early 1990s.
But it'd be a mistake for younger music fans to dismiss the music of Metallica and Guns N' Roses as dad rock (even if members of Metallica are doting fathers who have left behind their raging alcoholic days).
Modern metal bands that have gained significance in the past 15 years or so - from Norwegian band Kvelertak to progressive- metal outfit Mastodon - have waxed lyrical about Metallica; and French metal band Gojira's release this year, Magma, expands and broadens the template set by Metallica's genre-defining early releases.
Some bands at the top of today's rock heap such as Bring Me The Horizon might incorporate electronic dance music and pop flourishes in their latest songs. But the renegade rock 'n' roll attitude embodied by Axl Rose and Guns N' Roses in their early career remains the defining traits of many young rockers.
In the case of Guns N' Roses, the opening riff to one of its most famous songs, Sweet Child O' Mine, from the first album, is not only one of the most memorable rock guitar licks in rock history - it is still referenced in modern pop culture, most recently sung by the cast in this year's acclaimed drama film, Captain Fantastic.
Younger bands - from Finnish quartet Santa Cruz to comedy band Steel Panther - are taking cues from Guns N' Roses' template, from the twin-guitar riffings to the high-pitched howls of frontman Axl Rose.
Sure, some bands at the top of today's rock heap such as Bring Me The Horizon might incorporate electronic dance music and pop flourishes in their latest songs. But the renegade rock 'n' roll attitude embodied by Rose and his band in their early career remains the defining traits of many young rockers.
Guns N' Roses hail from the notorious Los Angeles glam-rock scene of the mid-1980s. Like a lot of rock bands from that time, they liked to dress up and looked like they spent a lot of time doing up their hair (hence the term "hair metal").
That came on top of a solid music foundation in the band's punk and blues roots - otherwise it'd have been a whole lot of empty posturing and Guns N' Roses' 1987 debut, Appetite For Destruction, would not have rocketed the band ahead of their Sunset Strip peers.
That album and Metallica's 1986 opus Master Of Puppets - still arguably the gold standard in metal albums - are highly original, innovative and pushed hard rock and metal into new territories.
In March this year, Master Of Puppets became the first metal album to be added to the United States' Library of Congress' National Recording Registry.
Besides the complex and intricate songcraft in the album, the themes explored in the lyrics continue to speak to listeners today - wars, drug abuse and crooked figures of power.
What's more, Metallica have a curious knack for getting people talking about them regularly, pandering to their loyal legion of fans as much as confounding them.
While they would gladly play full tours in which all the songs are pre-determined by fans through online polls, they have also consistently taken steps that earned them the ire of their fanbase.
In the 1990s, they cut their hair and started dressing up for photo shoots - to the consternation and anger of fans who liked their metal idols to look metal.
In the early 2000s, they came out strongly against Napster and online file-sharing, leading fans to accuse them of being greedy.
A few years later, the band's management hired a "performance-enhancing coach" and the footage of them undergoing therapy was used in a 2004 documentary film, Some Kind Of Monster.
Many decried the band for the move - metalheads are supposed to be stone-cold hard, not emotional wusses who rely on overpaid consultants to help them sort out their feelings.
These are canny moves. Generating controversy means people are talking about them. If people react to them with a shrug, that's probably a sign for them to move on or unplug the cables from that amplifier, hang up the guitars and retire.
Their non-crowd-pleasing actions also mean they are beholden to no particular group of fans, especially those from their past.
And how have Guns N' Roses confounded their fans and remained current?
Surprise, surprise, they now reportedly start their gigs on time, unlike back in the day when it was standard practice for the band to keep the audience waiting.