How long can I keep peanut sauce?
Much will depend on your recipe and how much preservative was in it.
My "easy" one depends on my partner having been to the Netherlands and brought back a jar of satay sauce. This is very thick - like peanut butter - and just needs thinning with coconut milk. I've kept the opened jar in the fridge for literally months (obviously not the thinned down version which wouldnt last at all well).
If I'm out of the jarred stuff, I use peanut butter, adding oil, sugar and lime, as well as garlic, shallot and chili. Seeing as the peanut butter is already laden with salt and oil, the finished product also has longish life. It's never lasted long enough to go off, but it's happily stayed in the fridge for over a month.