How much sugar should I put with the fruit in a pie or crumble? I just made a plum and apple crumble, which was delicious but I was worried it was going to be too sweet because when I was pouring the sugar in straight from the bag, it slipped and I ended up with about 50% more sugar than the recipe called for :-) 

In fact, though, it was only just about sweet enough - if I'd put in the amount of sugar the recipe called for it would have been way too tart.

I seem to find this a lot, and I don't have a particularly sweet tooth - I actually like things tarter than many people seem to. 

Does it depend on the fruit (if so, which fruits need more sugar?) and/or on whether the fruit was frozen or fresh?
All the fruit that's currently in-season is bursting with sugars already, which means I usually go a bit easier when adding sugar.

When it's mid-winter though, and you get the out-of-season/glasshouse variety fruit, adding a bit more sugar usually works well.