AI is highly personal to the individual. I've run 750mg sustanon a week with no ai - with water bloat, but otherwise no issues.
500mg test enanthate for me causes mild water retention - if my diet is clean. Too much simple sugars and excess sodium and I'll bloat a fair amount, but nothing to be worried about.
250mg test enanthate a week minimal bloat if I'm not running anything with it. Little face bloat, but some water retention under the skin.
AI is NOT mandatory on trt doses, let alone moderate to even moderate to high doses of test. It all depends on the individual. Some people's bodies are very good at balancing their test/estrogen ratio and handling higher than normal levels of testosterone.
Some people look at a vial of test and practically get gyno. Some people like me might use .125mg arimidex twice a week on 500mg test just to cosmetically reduce water retention - not as something necessary.