I think if truth be told my eldest ds (12) has always been quite self-centred but as he gets older he's gone from being a bit inconsiderate to downright bloody selfish. I know kids of this age aren't generally known for being at their kindest and life does tend to revolve around them, but it was really bought home when i had an operation recently and needed help and every little thing i ask he'd be the last to offer, would actively avoid helping (sudden need for homework/toilet etc) and not a single offer of 'is there anything you need/I can do?' despite seeing younger siblings helping out. I mentioned him lack of offers but nothing changed and he just didn't see the issue & one stand-out retort was "disabled people manage" 
. If you pay him to do a job he'll do it slightly more willingly but that's to his gain so I've stopped that & frankly he's quite lazy so would rather not have the money than have to do a chore!
So, I think it's time to try and force a bit of consideration on him and get him thinking about others a bit more but not sure what would be age-approproriate or helpful. All dc have a few basic chores such as putting away clean washing, tidying rooms, helping clear & wash-up after mealtimes and some weekends we will get them helping in the garden with leaf raking, weeding, cleaning cars but it's all an effort.
He turns 13 in a few weeks and we had planned on increasing his small amount of pocket money to a monthly allowance to cover more of his spending especially now he's wanting a bit more freedom, but i don't want him to see it as payment for jobs.
I was thinking something either like helping an elderly neighbour on a regular basis (doing weekly bins, going for tea occasionally?) a few more regular chores at home, probably a bit young for volunteering properly but something that means he gives his time & effort just because he can and thinks of others first.
Any thoughts?