There's an old joke about my profession (which can be used for any scientific / creative profession really): software developers are simply machines for turning coffee into computer code
Most professions have similar sayings:)
never in the evening as I don't want anything to keep me awake at night.
I've started following this too in the last few years. It seems to effect me for longer now and this is consistent with most nutritional i.e. don't take any caffeine containing drinks after about 6pm.