Quite a few have said not to take them unless you see side effects. However, I am of the opinion that one should take an AI from the beginning for several reasons.
If gyno develops, there is not a 100% guarantee that it can be reversed without surgery. This is where I feel running and AI would be very proactive preventing gyno rather than reacting to it after it already starts. Quite a few threads have passed through the Q&A about people who weren't having success treating their gyno with letro or tamox. You are also going to be using both dbol, which aromatases at a moderate rate, and 500mg of test, which you can count on to aromatase. I dont see any reason not to take a mild AI like Adex or Ldex at a moderate to low dose from the get go. I think that the majority of the gains people say you lose out on by taking an AI is simply a reduction in bloat. If you are using that much test I would recommend .25 Adex EOD or E3D.