So DSS and DSD have an allowance which we put in place after becoming a bit of a weekend cash machine, we decided then that we'd give them an opportunity to budget and prioritise what they want to spend their money on rather than them having to co me to us for everything.
DSD gets £50 a month, the deal is that we pay for "room and board" as we call it, after that she has to pay for her phone, toiletries, clothes etc. She also has an allowance from two sets of grandparents and her mum (£30 between them I believe). So she has £80 a month in total pocket money. 
She's just got her first part time job which is paying relatively well, she should earn around £150 a month. My OH and I are of the view that now that she has the means to pay for a few treats herself, we should reduce her allowance. After all, we put the allowance in place because she wasn't old enough to have a job and we wanted to give her a bit of freedom and responsibility. (That and the fact that she does have extremely expensive demands and I was a bit fed up with OH seeming to be asked for everything ALL the time by her)
When I got my first job at 14 though my parents stopped giving me pocket money altogether. That was fair enough. My parents gave it to me until I had the means to earn for myself. Once that was over I was on my own.
I should add that since we gave this generous allowance a couple of years back it's been a bit of a bone of contention. She blew most of her first year's allowance on a new iphone and then had no money to buy anyone christmas presents. Now all she spends it on is make up and clothes. The concept of the "budget" has been a bit lost on her.
I should add that she's not had to do any chores for her allowance - I know, we're idiots right?