Another "package" - set expiry at first use

I have another question about implementing another "package" :- Upon successful authentication, check it is firstuse. If yes, set expiry to say 6 months from now. Any advise how to implement this at the radius server ? My first cut thinking will be check 'radacct' for existence of any past usage records. If yes, set expiry 5 months from now. Anyone already has a mysql script written for this ? Regards