There are a bunch of rules I seem to remember about ability score maximums, but I can't remember where they come from or if they're actually the rules as written:
-
I believe there is a RAW that you can't exceed 18 on any of those either at creation or by buying points every four levels. For example I started with DEX 15, bought new points in DEX at levels 4th, 8th, 12th, and as for level 16th the cap of 18 will already be reached and I will have to improve another characteristic instead. Did not mention it but of course, racial bonuses if applicable can shift up the cap.
-
I believe there is also a RAW that you can bypass the cap by using a maximum of 5 tomes, making the real cap at 23.
-
Finally, for a standard human who bought 5 tomes and wears gloves of dexterity +6, the hard limit for its dexterity would be 29. (I purposely did not pick the example of strength because I believe there would be some way around it. Also in my universe, I have a way of getting one more dexterity point and reaching 30 but that is not the matter).
Are all those statements corrects, and (if so) where are they written?
Best Answer
No rules such as those you describe exist within D&D 3.5. There is no limit to how high any ability score can get.
I obviously can't know where you got the idea from, but here are some possibilities: