I just wonder who on earth would EVER upgrade lasers to neither THLs nor pulses. BASIC LASER DOES OVER 3x AS MUCH DMG AS A FULLY-UPGRADED PULSE LASER. Seriously, who would EVER, EVER do that. I don't understand.
And also, miners are more effective when not upgraded. Compare yourself.
Eg. 3x basic miner = cost 135m / 240 mpm
and one upgraded one = cost 145 / 200 mpm
So, upgrading the miners is rarely worth it.
That would be memorisation!