Entities limit, any tips and tricks?

Any way to control the limit? or to keep an eye on total entities?
Also any tips and tricks while working on them?
I see someone talking about effects in loop, what does that mean?

Whenever you add a “create effect” action you note it down in a .txt or something. The limit is 128 effects/beams/icons and 128 hud/inworld-texts.

You should look up the explanation of a loop in google or something. Should not be to hard to understand.
“Effects in loop” usually means “Creating effects in a loop” wich is used to create a lot of effects with only few code lines, but conflicts with reevaluation.