How long should it take to build up calluses on your fingers? I know that it depends on how often you play, but I play about an hour everyday.

I would bet that you have calluses, by now. I have forgotten how long it took for my fingers to develop calluses. A tip I would give you is to resist the temptation to pick at your calluses, (like one might do with a scab.) I even file the calluses on my finger tips to keep them smooth and prevent the skin tabs that makes picking at them tempting. When I do pick my calluses off, it seems to take about a week to get back to where they won't hurt.

About 1-2 months if you play consistently.