The question often comes up, “How often should we have the piano tuned?” The answer is really as simple as, “As often as you want it in tune.”
People seem to have no problem tuning their guitar every time they play it, accepting this as normal while at the same time, after several years, wonder if it is time to tune the piano yet.
Many performance pianos are tuned perhaps monthly or more often than that even.
The less casual pianist at home usually can do alright with tuning once a year however, when they air-conditioning goes off and the heat comes on, the piano goes through some significant upheaval. As well the reverse is true so you will have the most consistent result by correcting the tuning on your piano after the two major seasonal changes. If you wait until December and then until June you can beat the worst of your tuning issues due to seasonal change.
Tuning costs vary a little depending on distance and how long it has been since the piano was last tuned
Repair of various mechanical problems are considered generally not part of the tuning process and therefore are billed over and above the cost of the tuning service call.