Thanks c9h- I forgot about that link. It's great. I used it a long time ago, but really should get back to using it more often,as it answered my question perfectly.
By 5th street, absent a good read on my opponent.the odds
are stacked like this:
600,000 trials (Randomized)
Hand Pot equity Wins Ties
**77T 37.54% 225,168 112
5-5-TJ9 62.46% 374,720 112
So, assuming a full table of 8 and in my case, a .25/ .50- .05 ante and assuming I have bet/call(4th), check/call(5th), the pot by 5th street has at least $1.40 and at most $2.40, so if I check call all the way to 7th street, I'm just about getting (or nearly getting) proper odds.
On the flip side, if you have something like 5-6-7 in the hole and I pick up the 7 and a 10 on 4th and 5th respectively, are you raising on 5th to represent two tiny cards in the hole? That's my typical MO.