for me, the minor "second thoughts" seem to be normal.. When they get strong, I take it as a sign to back off and take a break.
A typical scenario has been 6 to 12 weeks at or near my top dose, some "what the hell?" thinking, ramp down over 3 to 5 days, off for 5 to 10 days, and ramp back up over 5 to 7 days.
I've found that following my gut seems to be good policy... I'm usually rewarded with a growth spurt, starting within a week or two after being back up to my full doses.
I just finished off a 10 day break and have been back up to full dose for about a week, and I have already noted signs of increase - a little more heaviness, and definite depth between the girls - signs not there before the break. Budding soreness is also just kicking in again.
Short breaks are a little closer to cycling - a 5 day break is barely enough for the budding sensations to subside, and they are usually back after the ramp up.
I always go into a break recognizing the possibility that I may not come back from it, but I'm old enough to know that "never say never" is also good policy!
-j