We have a pressure-treated lumber second floor deck that we think is about 22 years old. It was stained 5 or 6 years ago, but we don't know about any previous maintenance.

There are 3 boards with rot that need to be replaced and a lot of boards with many small cracks. However, the bottom of the boards and all of the joists look good.

Someone has recommended replacing the few boards that are clearly rotting, and then turning all of the other boards bottom-side-up, and refastening them. Then we would stain the "new" top sides.

The idea is that this will put off a full replacement by about 5 years or more. Is this a reasonable idea? Is there any major downside to doing this?