3V3 to 5V level conversion
My experience with HD44780 and  S6B0107/S6B0108 (= KS0107B/KS0108B) based displays is that they don't work with 3.3V logic levels.

I put a 1k pull-up resistor on each pin and use the pins of an LPC1114 in open-drain mode. This works fine for me.

A professional will do what is appropriate for the situation. IME a high-volume design will combine a 3V uC with a 3V display. For low-cost designs you could check the Nokia 5510-style LCDs.