I think it's a judgement call. I don't cycle, but when I blast I use Aromasin; when I cruise, on 400-500 a week, I don't. But the reason I don't is because even at 500mgs per week, my E2 is below 40 and I can't afford a steady diet of Aromasin. When you cycle, you want the max gains in the shortest amount of time. So even if you use a moderate dose of 500mgs a week for 16 weeks, plus some other gear, you can probably get away with no AI but would be harder and stronger with an AI. The only way to know for sure is to get blood work done while on cycle to see what's really going on. The cost is relatively inexpensive and takes away the guess work. I'd get blood work done maybe during week 4-5, and if your E2 or other tests show you need to place certain controls, then at least you know what and about how much. You'll get results within 48 hours.