I check them all. Takes a few seconds with a pin. In the winter I use a proper balancer when I resupply the stock. I have also found some brands are much more consistant than others. XOAR wood has impressed me greatly (all have been balanced). APC is pretty good. ProZinger usually is but I've had a few doozers, but wood is subject to that.

Of a dozen props maybe 7 to 9 will be OK as is, three will need some work and one or two will need material removed and 10 minutes of futzing.