I think a lot of us who have been collecting for years would have a hard time saying it’s a good time to buy: prices are high, market could become flooded, etc. However, I thought this a year ago and prices seem to have only increased since then.
I think it really depends on you, is there something you really want that if the value decreases you are still happy you made the purchase? Or, do you even care what the value might do? Also, it may be a good time to buy because items are available that may not be sold off at others time because the prices have risen. Might be an okay time to focus on the non-major franchises that haven't seemed to appreciate as much.
You are welcome for this non-answer.