Depends on the particular goal of the cycle. Mass or cut?
Estrogen has profound beneficial effects for mass gain, though fat gain, water retention and gyno are obviously unwanted. It does support glucose utilization, gh release, androgen receptor proliferation, and a well being feeling/energy. These are benefits of slightly elevated levels... Not ridiculously high that has another laundry list of health issues.
If we are cutting than yes lowered levels of estrogen are more desirable which is why generally non-aromatizing steroids are used heavier in a cut cycle.
Suppression of estrogen when not needed in my opinion is a waste
It SHOULD however be managed properly with blood work.
Arimdex is an aromatase inhibitor
(blocks the enzyme aromatase, preventing conversion of test to estrogen) effective and strong 1mg can drop estrogen a significant amount.
Nolva is a SERM
(binds to the receptor, preventing estrogen to bind, but does not stop conversion) used very commonly for prevention of gyno and/or reduction.
Both can be used for estrogen management but quite different. Arimdex is more effective, but can be harsh to the beneficial side of estrogen. Nolva won't ever crash estrogen but also won't prevent high levels.
This is why blood work is important, we can all give you suggestions on how much to take based off our experience but that's IT. it's our experience and you will be different. There are just too many variables to be accurate. This is not something we'd want to play guess with.
Blood work is a must if you want to:
1) be healthy and safe with cycling
2) get the best results with your cycle.