Is there a way to test deck wood to see if power wash is necessary?

How long should one wait before sealing or staining decks and fences - is there a rule of thumb with how quickly grime sets in where you have to treat the wood first before staining.


Any opinions on what to use other than power washing to clean the wood.


Also, since oil-based stain is going to be banned, what water-based stain and colors work well and how long do they last.Is there a way to test deck wood to see if power wash is necessary?
If you used a good quality of pressure treated wood you can stain it right away. All wood decks should be cleaned and sealed every year if not then 2 years max, that is why everyone is going with the composite decking for their decks now a days. No or very little maintance. It may cost a bit more at the begining but in the long run it will be worth it.Is there a way to test deck wood to see if power wash is necessary?
My rule of thumb is that if it is a wood deck it ALWAYS needs to be power washed and sealed or stained. It seems that way anyway. The composite materials mentioned above are the way to go.