There are some things that come in jars that I like, but I don’t use very often. Soy sauce, sweet-and-sour sauce, some salad dressings, etc. How long should these things last in the fridge? There is no information about this on most labels.
Soy sauce has a high salt content and will generally not go bad.
Not sure about the other sauces.
You don’t have to worry about stuff with a ton of salt or vinegar, like soy sauce. (I don’t refrigerate mine.) Salad dressings and such have expiration dates on them - a creamy dressing is definitely off if it separates (not the olive oil stuff that always separates, like italian dressing, etc.) Sweet and sour sauce lasts a long time, probably because there’s not a lot of actual food in it. 
And good old MSG!
This site is likely to answer all your questions.
While this is generally mostly true, I have seen high-vinegar sauces like salsa go moldy on occasion. Of course, mold is pretty obvious, so that makes the procedure a simple matter of “Look at it. If it’s moldy, throw it out, otherwise, eat it”.
Soy sauce, though, I can’t imagine that there’s much that could possibly go wrong with it at all. Not only is it too salty for most things to survive in, it also doesn’t really have enough nutritional value to feed anything in the first place.
Just curious thread starter, are you filipino? “on the refrigerator” sounds like a tagalog artifact.
No, I’m just a poor typist.
What country? In the US, every single food item I have has an expiration date, and imported foods from other countries are required to have stickers in English with FDA-required information.
They often don’t say anything about how long they last once opened.
Ooh, that was so useful I’m bookmarking it.
(The answer to my own question: pasta sauce keeps for 7-10 days after it’s been opened. And apparently should not be stored in the can.)
I had something growing in high strength pure vinegar in the fridge once. After I threw it out, I started wondering if perhaps I might have inadvertantly threw out the next penicillin or super microbe.
I made some hovmästarsås a couple of months ago, and there’s still some left.
It’s made of Dijon mustard, vegetable oil, red wine vinegar, sugar, a little salt and pepper, and dill. Since it’s mostly vinegar and oil, I assume it’s still good?
I had some honey mustard go bad on me once, still with the original factory seal. Unsweetened mustard I’d trust, but with some sugar in there too, it’s possible for it to spoil. That, I’d give the smell test. If it still smells how it’s supposed to, I’d probably eat it.
[smartass] You’re asking us? I doubt most Americans have ever eaten anything that’s spelled with an umlaut and the little circle over a vowel… [/smartass]
As for your question, I dunno… I suppose it depends on how much sugar and salt you used, and whether you used dill flakes or the fresh stuff.
Well, it’s too late now in any case! 
burp
This may be helpful:
http://www.axis-of-aevil.org/misc/tableofcondiments.html