As an Australian, I like to follow British forms of words such as license/licence and practise/practice. I have no problem with licence the noun and license the verb, but I find it hard to keep practise and practice straight.
To get better, I practise my juggling. When I see a doctor, I visit their practice. But what about preparing a set of practice problems? Are they a set of problems that are used for practising, being instead practise problems? Is there a use of the word practice besides referring to, say, a doctor's establishment?