With summer right around the corner it is important to check your doors and windows for any signs of failing paint or stain finishes.
Wood windows and doors that are hard to open and close will typically have signs of failed paint or stain finishes which cause the wood to swell and eventually fail at the joints. If not properly maintained this could turn into replacement rather than repair.
Areas that receive excessive exposure to weather (sun and rain) deteriorate faster than areas that are covered from exposure.
We also notice here in Southern California the southern facing doors and windows need more maintenance than the northern facing doors and windows.