Every substitute will relate to this story by new Munster signing Tadhg Beirne
Sometimes in life you've only got one chance and it's up to you if you take it or not.
Tadhg Beirne knows the feeling.
He spent the latter part of his teenage years and his early 20s striving to make it as a Leinster player.
Four substitute appearances came in 2015/16 but no more than that. No starts and certainly no run of games to bed into the team.
Beirne was told there would be no contract for him at the butt-end of the season. He considered packing in rugby to concentrate on his Masters but got a late offer from Scarlets and made the move abroad.
Listen to the full interview below from 34.20.
"I just wanted to come over here, have a crack at playing and start enjoying rugby a bit more again," Beirne told The Hard Yards. "Because I was getting to a stage where it was so frustrating, never being involved and not getting the game-time I wanted to get and it got to a stage where I was enjoying it a lot less."
Beirne feels he can pin-point the moment where his Leinster career was almost over before it began. His recollection of his fleeting appearance against Cardiff Blues, at the RDS, will resonate with so many people that have tried to impress off the bench.
Former Leinster forward Kevin McLaughlin, who came close to quitting rugby before finally establishing himself in the senior side, likened the pressure to perform in short bursts as 'being under the gun'. Beirne agreed, saying:
"It was my first cap for Leinster and I was on the bench against Cardiff. I was obviously quite excited. You're so nervous too and, as you've said, under the gun. You know you need to perform.
"It got to the 60-minute mark and I wasn't getting on, and it got to 70 minutes and I still wasn't getting on. I was getting a little deflated as well. You know, your family comes over and you're excited to play and you feel like you're not getting a proper chance to prove yourself.
"I came on around the 74th minute and the first thing I did was make a blunder of a mistake. I had Jamie Hagan inside me, who was obviously out on his feet at this stage. I shot out of the line and Cardiff made a line break.
"I just felt ever since that game, the coaching staff never really trusted me as they should have because of that mistake. I think that probably hindered my chances at Leinster."
Leinster were 16-15 up at the time but rallied, with Beirne's help, to get a penalty try and win by eight points. Six minutes of rugby, on debut, and a rollercoaster experience.
Leinster deemed him surplus to requirements but, less than 12 months after being cut loose, Beirne returned to the RDS to help Scarlets defeat his old team in the PRO12 semi-final. A week later, he scored a try as Scarlets won the league title.
When Joe Schmidt spoke with Beirne, earlier this year, about a return to Ireland, he zeroed in on a switch to Munster. One feels he still has some stuff to prove to his old club.