At 40 years old my opinion is I wouldn't even bother with using steroids AT ALL if you're not basically going to be on them permanently - blasting and cruising.
I don't care what anyone says - you will not be able to hold supraphysiological levels of muscle mass, nor retain the steroid look when you come off. It won't happen. Your natural test production will not support it.
Yes, judicious use of cycling and proper pct can get you to your natural limit FAR faster, but even then, regardless, you've been messing your endogenous hormone production which may very likely come to bite you in your ass with decreased hormone levels earlier than you otherwise would have experienced. I believe this happened to me as I began to seriously start noticing a lack of energy, muscle tone, and increased aches and pains beginning around age 39 - which might just be a part of aging, but also I believe my past cycling contributed to that happening sooner than necessary.
IMO, either go all in, or don't bother playing with the stuff.
I know many guys would disagree with me, but what's more responsible - staying away from peds, or intelligently and seriously making the decision to permanently go all in on them - versus going off and on the gear causing hormonal roller coasters and potential hormone downregulation sooner in life than need be?
Regardless, I wouldn't recommend anyone earlier than their mid to late 20's even try steroids.