My son's football boots have got to go.
Why would you get rid of your son's football boots?
He has been playing with them since last year, and he's never good at it. It's time to get him something else.
Are you sure the boots are to blame for his playing performance? You shouldn't just take your son's boots without talking to him first. Try having a talk with him to see if he thinks the boots need to go.
I can buy him other ones.
If football is something he enjoys but is bad at maybe you should consider finding someone to coach him. That seems easier than throwing his boots away and then buying news ones.