For the life of me, I have trouble understanding why folks would do "cold turkey" for stimulants rather than tapering their dosage off over a week or two!
Personally, I have a hard time with moderation, and doing things gradually. I'm very much all or nothing, so it's easier for me to say "no caffeine in any circumstance!" than "okay just a little caffeine each day", because at that point it's easy to convince myself "well half a cup was fine, so just a sip more won't really make a difference."
Exactly the same for me, but also the approach to alcohol. Moderation is not something that works - either I 'forget' or the it snowballs. Therefore, decaf coffee (seems okay) and no alcohol.