Hard to say, as everyone is different, but if you are getting into cycles that are longer than 6 months, you are going to risk doing some damage to your HPTA. You can only ride a high period so long before you end up at a low. As for other compounds, EQ is probably going to have less of a chance of side effects, and the results are going to be similar to deca. Using one of these is a great idea, as they are going to have a more anabolic effect on your muscle, than just using test alone. These comounds are great for adding more muscle. So is Dbol, but I would only use it for limited times, being an oral with more potential sides. If you have never used EQ before, adding it in at 400mg would show a difference. Now keep in mind, this is going to take time to kick in. I usually see good physical results from EQ after 6-8 wks, so adding it in would require taking your cycle that much longer. Maybe it would be a good time to take a break, PCT, then when you are ready, start back up with test eq and even 30mg dbol for the first 4 wks