How to know if you're a good Support players

Wards Count

With each game no matter, the minimum of wards you should had per game should be at least 15-20 to be a good support players who constantly wards

Maximun should be 30+ since the ward timer and changes since the past patches you can't really reach 40+ ward anymore unless the game go to a long extension

KDA

Just because you play Support doesn't mean its ok to feed (By the end of the day, you're worth just as much gold as any Player in the game)

If you have the least assist than your adc or solo laner in most of your game, you're obviously not doing your job right.....either not using your abilities to help team mates during dps or you're just watching from a distance of fights happening (Unless you're getting the kills)

But especially the Wards Count

If you don't meet that part, you're obviously not a good support at warding even if you're winning matches without warding that much.

Vision win you game still