If by tolerance you mean taking it more often then I can say that no matter how long you take a break, the buzz starts to wear off after the first one or two times.
Yesterday, after not taking any gabapentin for at least 3 months (and having only 4-5 experiences) I got 90 600mg from the pharmacy and took almost 9,000mg throughout the day. Now that was a dumb idea taking that much for a few reasons but what I'll say is the good part never came (why I continued dosing throughout the day). I seemed to have skipped right over it and ended up stumbling around, thinking the WEIRDEST shit, and unable to fall asleep. Needless to say the magic was gone and I'm just gonna take these therapeutically from here on out. That's my experience..hope I could help