You can get LCDs that only need two wires.
... and they are simpler to program. They cost a LITTLE more... but this is a wheel you DON'T have to reinvent, chores you can pay someone else (a little) to Deal With...http://sheepdogguides.com/arduino/art8lcd117.htm
Your subject... "pin limits" made me think you might be interested in current limits, so, for anyone checking the thread for that, here's a neat little "gotcha"...
Each pin must not be asked to carry more than a certain current.
BUT! Even if you keep the current in every pin below that safe maximum, you can STILL get in trouble if you have too many pins near the per-pin maximum at once. There's a total-current-through pins, too, which is LESS than "number of pins TIMES max per pin"