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I think you are thinking about this the wrong way. People become caffeine tolerant quickly, but tolerance goes away pretty quickly too. You would get more benefit out of the opposite approach - spending most of your time without caffeine, but drinking a cup of coffee rarely, when you really need it. You would effectively be caffeine naive most of the time, with brief breaks for caffeine use, and this never develop much of a tolerance. If it's been a long time since that first cup of coffee that you don't remember it, trust me, the effects of caffeine on a caffeine-naive brain are incredible.
I know I once read a study that says you can get back to caffeine naive in two weeks if you go cold turkey, but I can't find anything on it again for the life of me. I do remember distinctly that going cold turkey is a bad plan, as the withdrawal effects are pretty unpleasant - slowly lowering your dose is better.
On a more practical level, it is certainly possible to have relatively little caffeine, such that you aren't noticeably impaired on zero caffeine, while still having some caffeine. The average coffee drinker is far beyond this point. I would try to lower your daily dose over the course of a month or so until you are consuming less than a cup of coffee a day - ideally, a lot less, like no cups of coffee. Try substituting tea (herbal or otherwise) if you need something hot to drink to help kill the craving - herbal tea has no caffeine, black tea has about 1/4 of the caffeine per cup, and if you add cream and sugar the taste will be familiar.
EDIT: VincentYu's comment above is interesting in light of this. I am not going to perform my own meta analysis on this, but there are a great deal of studies that find that caffeine tolerance and caffeine withdrawal are real things - a quick Google Scholar search for "caffeine tolerance" will find them.
I am now very interested in a large study on this without the possible conflict of interest. Also, I find it odd that they choose to not include studies before 1992.
Yes, a cup of coffee is too much.