Firstly: Invernessian. Lulz...Some fackeen weather we're haveen this "summer" eh!
Secondly: I totally get what you mean regarding the tolerance. This applied to when I was younger (around your age) when weed started turning on me a little, after a good few years of heavy, heavy smoking. It made me CRAZY anxious, feel like I couldnt breathe etc etc...
I had a break and came back to it....
Now I love it again!
When you have a tolerance, indeed you do lose the spiritual founds upon which goodly cannabis use can foster and build. However, if you smoke only to recreate pleasure and enjoy one's self, then a tolerance can be a rather welcome thing, certainly.
Cannabis can be a terrifically insightful, useful substance under the intoxication of which, you really can reveal your innermost resources to yourself. Make grand use of this wonderful herb. It sounds like you already eulogize and applaud it's benefits.
Just ensure it stays that way, so as you don't become a chauffeur merely driving automatically with no great exploration of your universe.