There are so many variables to take into account when or if you stake your trees.

First, size of the tree.

Location. How protected is the area in question.

Time of planting, Fall or Spring.

Is your tree a bare root or does it have a good-sized root ball to help stabilize the tree.

What type of soil do you have, loose and sandy or clayish and heavy.

How often do you get Thunderstorms with high winds and how unnerved would you become every time a rain or storm comes up and you think about your trees standing out there. :-)

There may be other factors involved that are unique to your geographical location too.

We have TS here with down bursts, microbursts or whatever the name and they can locally deliver wind speeds of 80+ mph. This is not a common occurrence but does happen occasionally.

I wouldn't stake a tree for more than a season or a few months into the next season. Unless it is an extremely open and windy area with it being a tall or windsail of a tree.

Generally speaking, if a tree is planted in the Fall, there will be root elongation until soil temperatures drop to near freezing. Depending on how early or how late it was planted in the Fall, determines how much the roots will grow before winter.

New roots form in the spring, so a tree planted in Spring, while still in dormancy or one that was planted the previous Fall, will grow new roots all that season and then again, elongate the following Fall.

Therefore,

If I had trees planted the previous Fall, in an open or windy area, I would stake or somehow protect them for all of the next season. The following season they should be on their own depending on some or all of the variables listed above.

:-)

I'd put a stake on them -- one to bring back to straight would prb'ly be sufficient. In a couple years should be fine.

What strikes me about the OP is that a lean of more than 45 degrees would require something that looks more like 'a new planting' rather than 'a straightening'.