All other things being equal.. and for a tournament which is NOT a qualifier and has a "standard" payout structure.
If you assume that all the other players are of the same standard as you (not a bad assumption because your edge is very small) then you work out the rebuy/addon overlay..
In essence you watch the total amount of money going in rebuys and assume everyone will addon.
You need to get fewer rebuys than the average player - if you do that then you get an "overlay". If you exceed the average number of rebuys - then you are subsidising the tournament.
The addon does complicate things. If the average number of rebuys as you approach the end of rebuy period, is 3x what you put in it can be worth taking less than a coin flip to double up. However - for most tournaments I've seen the average rebuy is usually about 1.5 ish. This means that TYPICALLY -you should rebuy once - and addon...
There again ppl accuse me of taking a money grabbing/cynical attitude MTTs (the most famous thread ever posted here - it ended up on TV!!-) was about me corrupting the nobel art of MTT's
As a caveat - remember I go out to win money - the process of winning an MMT has no value to me other than its effect on the bottom line...