I hit my limit on the project I've been working on (after I let "MAX" run out and moved to "PRO") after about only 2 hours!
TIP (YMMV): I've found that moving the current code base into a new 'project' after a dozen or so turns helps as I suspect the regurgitation of the old conversations chews up tokens.
An aside: https://www.buchodi.com/chatgpt-wont-let-you-type-until-clou...
It seems that anthropic has added something similar to their browser UI because just in the last few days chat has become almost unusable in firefox. %@$#%