Spending one’s whole pay on self indulgence does not make for maturity or a pleasant person.
I can second that, though of course increased savings are an option.
My BIL is getting incredibly cheap board - £120 a month - out of approximately £750 take home. Age 19, he is into heavily branded and designer clothes.
He requested designer gifts for Christmas. My husband couldn't find one of the things he wanted, and was fretting about the (designer) substitute he got. Said he hoped it was ok when BIL opened it. BIL gave a very sullen thanks. Then perked up when he opened the 'right' gift next.
What did he get us? Some £10 piece of tat from Tiger between us.
When I see people on here fret about their 'DC deserving nice things, why shouldn't they have nice things just because they're younger', I wince. It's character building to work your way up the ladder of life!