When it comes to the maintenance of wood windows, there are three tips that really come in handy. Old wooden windows were made of a higher quality of wood so it is more cost effective to maintain them, rather than replace them.
Every 6 months you should inspect your wood frame windows, both inside and out. Check for gaps, warping, insect infestation and peeling varnish. Once you notice peeling paint or finish, it is time to repaint. You do not need to remove the old paint or finish, simply paint over the existing layer. The finish repels the water, keeping rot away from your wood window frame. The rotting effects are larger and larger over time, so it vial to repaint at the first signs of wear.
Wood has a tendency to warp over time. This can cause spaces between the frame and the wall, resulting in air leakage. The leaking air will not harm your window; however it will cause your energy costs to increase as you combat the warm air you are losing. The best way to solve this problem is to caulk the tiny spaces and fill the larger ones with foam. The foam will not only plug the hole but also act as an insulator.