Given that Ipe is one of the hardest and densest wood species available for outdoor projects, careful preparation is essential. Here are the recommended steps: 

1. Sanding: Use 80-grit sandpaper to sand the Ipe wood deck. 
2. Pressure washing: Perform a pressure washing to deep clean the deck. 
3. Oil treatment: Apply Osmo Decking-Oil in the color of your choice on the day after the pressure washing. It is important to choose a colored oil to protect the wood from UV rays. 

If the deck has been treated before, start with a pressure wash followed by an exterior stain stripper, then follow the wood preparation steps mentioned above. By following these steps, you should be able to effectively restore your Ipe wood deck to avoid having to redo it every year.