How long to rehydrate foods?

[Grasshopper2Ant]

Please tell the methods you use to rehydrate your dried foods and how long it takes. 

Thanks.

[LvsChant]

I pour boiling water over the veges and let sit (covered) for about 15 minutes for some things. Things that are going into soups, stews, etc., I just dump in.

[JGreene]

I'm rehydrating some onions.  From what I understand, I should soak them with an equal part of water for about 15 minutes, but the texture is not like a freshly chopped onion.  The flavor is there, but its still flat.  Perhaps I'm expecting too much??   

What should I expect from potatoes? 

[Thox Spuddy]

I always do it overnite. Some things can be done in minutes followed by boiingl them, but some denser veggies, like carrots or sometimes even potatoes don't fully hydrate that way. Overnite you are guaranteed success. Onions don't take overnite, and I often don't hydrate them at all but saute them in oil, very quickly as they burn easily.