Whether you eat it, compost it or donate it to Second Harvest, please pick all the fruit from your fruit trees each year. Old fruit left hanging on the tree can become a home for diseases and pests to over winter and cause harm to the tree in the following years. The tree also puts energy into supporting the fruit until you pick it, so give the tree a break and harvest as soon as the fruit is ripe. We are also having quite a hard time with rats around here, so removing excess fruit will eliminate a food source for those varmits. Fallen fruit is also a source of nutrition for molds and bacterias so rake that up as well. The same goes for ornamental fruits and berries.
In early spring/late winter just before the flower buds begin to open spray deciduous fruit trees (not Citrus) with dormant oil spray to ward off leaf curls and pests. I usually remove any curled leaves from the Peach Tree by hand as it is a small tree. This seems to help a lot and is in addition to the oil spray. Our little Peach tree is my favorite and my daughters and I eagerly await the lovely and delicious fruit each year. It gets very heavy with fruit and so I thin out the fruit by more than half and prop it up as best as I can. Even then it has had some broken branches. Thanks to Dan Hoskins, my trusted tree trimming buddy, it has been successfully re-trained several times. To me the Peaches are the equivalent of garden gold.
Deciduous fruit trees are usually pruned back by 1/3 each year in January and the Sunset pruning book is a good guide. Citrus are just shaped to have a nice round canopy and any dead branches are removed. Do not open up Citrus canopies and expose the branches as they can get sun scald which makes the bark peel back. Deeply water all friut trees in the summer for good fruit production and the health of the trees. After all, fruit is full of water!