My record for one I've actually solved is like 6 months working on a problem (on and off). I'm actually more of a physicist than a mathematician (although my wo

My record for one I've actually solved is like 6 months working on a problem (on and off). I'm actually more of a physicist than a mathematician (although my work is all about proving theorems and lemmas), so the objects I work with tend to be at least possible to play around numerically with for special cases.