In my case, determining the period of time between making changes to our house is easy: my wife tells me when to do it. Her criteria is usually when she sees what one of her friends has done.
But if you want a more logical approach, here are some of my thoughts:
(1) Always try to keep your house in a condition where it could sell quickly. That means keeping the general maintenance current and the decorating reasonably "fresh". We tend to paint a room every four years. I always try to look at our house as if I was going to buy it again.
(2) Don't renovate so that you have the most expensive house in your neighborhood.
(3) I've found that getting rid of "clutter" makes everything look better. When things are cluttered, my wife thinks its time to do something.
(4) We generally replace appliances when they stop working. Having said that, we once did a kitchen renovation by refinishing the cabinets and changing the sink and counter top. It was worth changing the appliances to a more modern look to complete the project.
(5) Children (having them) or (becoming teenagers) or (moving out) are good times to renovate. It's also the time your furniture needs to be replaced.
I know this isn't exactly what you want as an answer, but I don't believe there is any one size fits all answer. We have a couch we bought when our children went to college and was fine until we moved near our very active grandchildren. Now it needs replacement.