I tend to look around and see what everybody else has planted and watch how it is doing. It seems most every locality has a different variety of Apple, almost down to a couple of square miles. It pays to ask the local Garden club, the large retailers sell consumer friendly trees which may not work out well in the long term.

At least around here the green or tart Apples seem to be later Apples. Many of the half wild varieties are the healthiest and most prolific, even if the Apples are a little small. Apple trees are a lot of ladder work, I need to trim mine at least twice a year.

Pear trees grow slow and are prone to disease. I've seen very few large, or healthy Pear trees this far north. Even the very old ones are small.

Plums are fast growers, the European varieties are pretty much bullet proof and tolerate the cold well.

I found a sweet Apricot tree that did well in the cold, my darned dog decided he liked the bark, ringed it and killed it. Really tasty Apricots and I'm not a big Apricot fan. I wish I could find another, it was likely a hybrid, the Apricots off of that tree were almost as sweet as Peaches.

Pollination is a big deal with fruit trees, you have to plant them in pairs and dissimilar pairs often pollinate better than two cloned trees. Whole studies done on what pollinates what the best. When you plant dissimilar pairs they need to flower at around the same time for best pollination. Some trees flower early, some a month or more later. Finding non cloned pairs that flower at the same time can be interesting.

My neighbor was a big Apple tree grower (died at 96), he had many trees grafted so they produce two kinds of apples on the same tree and could cross pollinate themselves. A single tree produced a whole bunch of Apples.