It's not hard to tell who buy tokens and who not. If the bidder you're against has a Q about 6 or more stars (total quality) then he buys tokens. Not hard at all.
Point is to understand if the guy is bidding for a plus or he's bidding for a VERY NEEDED player. it's easy to just open your opponent's team and check if the auctioned guy would be a reserve or a main in his team. He will most likely spend not many tokens to get a reserve, and your 10 might be enough.
On the other side, depends on what you're bidding for. If you try to go for a 18yo 5*, it's just you being dumb to start that kind of auction having just 10T, since they go from 25 to even 150.