yes I too started by not always digging those nickel signals, but when I started I found alot of nickels and two gold rings....along with alot of PT's and other junk.
Yes, I should have qualified my response with if you do not dig pull-tabs you risk missing some good finds. Zinc, I do very often dig and have made some good finds. Now and then I do dig a pull-tab but not often.
I dig nickels, of course along with the thousands of aluminum targets. I pay attention to the ratio of nickels to quarters. If I'm in a park finding nickels but few quarters then I assume the place has already been hunted.
It seems quite a few MDers will pass up nickel signals. No one passes up quarter signals.