I wanted to start this discussion because so many of the posts on here seem to infer that this type of thought process is being ignored.

at the highest level:

A: you get the best value for producing vets in-season, when their production is the focus and the draft is miles away. people are focused on winning. this trend continues up the closer to playoffs you get and the better teams can project their chances of contending. This value curve is more exponential for older players than it is for younger ones (their value goes really low in the off-season and then skyrockets when they are top 10 at the position again).

B: you get the best value for picks in the off season, when there is nothing to do but focus on the draft. this trend continues up the closer to the draft we get as we get more information to project onto these players.

Price-checking vets, especially non-elite vets (but even elite vets) in the off-season seems like you are exploring trades at a players lowest value. If you were not a contender, they should have been moved last season. If you were a contender, and made the decision to keep a vet despite the reality their value might never be as high as it was, then you should have made that decision knowing that you were likely going to have to hold that player and hope for the best.

Some real life examples from recent reddit posts AND my actual league:

1. Brandin Cooks: although Cooks is the topic of perennial undervaluation, if you own him trading him now is not the right time anyways. On a contending roster Cooks is an ideal acquisition of a safe producer (in theory, next year) and somebody who wont cost you a fortune. I've personally sent some counter offers to trades that included cooks, thinking "oh the WR 20 should get this done" and have gotten laughed at. oh well, holding it is.
2. James Conner: what a sick 2021. If you were a contender you likely tried to ride him to a ship and if you weren't you likely cashed in on what was basically a free player on your roster. either way, if he is on your roster now, exploring trades for a guy who is without a contract and who was written off just 12 months ago is not ideal. Seems to me holding to see where he lands and likely continuing to hold to see if he repeats his performance is the ideal decision.
3. Insert any RB over 25 or WR over 28. Even the valuations on guys like Tyreek, Adams, Diggs, etc are all wack right now, despite them in all likelyhood having great years next year.

Obviously you should be exploring trades. People overpay for guys all the time. But let's collectively start looking at players values with the lens of the time of year we are in.