You probably don't need new tuners. 99% of the time you only need new tuners if one or more break. Those appear to be in good condition. If they are hard to turn, disassemble and clean it, being careful how it comes apart so you can reassemble it properly (you can leave the plate on the headstock.) If you are having a hard time tuning and the tuner goes from flat to sharp in a sudden fashion, loosen the string and move it out of the nut groove; then use a number 2 pencil and coat the nut groove with the pencil. You can them put the string back in place and retune. Remember, always tune UP, never down; there is something called lash (it's play between the gears and EVERY tuner has it, regardless of the cost) that can, rather WILL, cause the string to go flat if tuned improperly.
When reassembling the tuner do not oil or grease the pieces, if you think you need some lubrication use paraffin or candle wax.
