If you have a big jar of sauce and you’re only using small amounts for pizza then definitely freeze after opening. You could even portion the jar out into smaller amounts using ziplock bags or ice cube trays!

until visible mold and / or bad smell

depends on whether it’s a store-bought with preservatives or something I made at home - fresh stuff lasts maybe a 1 - 2 months max, store-bought could maybe last 3 months at most?

I find pizza sauce and other red sauces like that don’t tend to last like 4 - 6 months, they tend to get mold growing on the top. Even my tomato paste gets mold, so I like to put a little vinegar on the top (like you would add lime juice to guacamole to prevent it from oxidizing and browning), and that usually makes it last much longer / prevents mold. (Yay for acetic acid!)

2 weeks with a good fridge. Though maybe longer if I was desparate. The smell test should be enough.

I’d definitely toss it if it smelled off or there was mold in it. Otherwise, I’m probably using it.

Get a dedicated ice cube tray and freeze leftover sauces like that if you aren’t going to use them often. Pop them out and put in a sealed container or freezer bag as soon as they are frozen. The small size gives you freedom to thaw what you need.

There’s no set limit, not in days. Weeks, yeah. Generally, you’ll start noticing it tastes off after about five to ten days. It won’t necessarily be spoiled, but once opened, everything starts losing freshness fast, relatively. Safely wise, a week is what most people say is the cautious limit. But the truth is that if your fridge is stable, the jar didn’t have anything dipped into it, and it isn’t being opened frequently, it could potentially last a month or more without being dangerous to health.

However, it could also grow shit overnight that would make your toilet very unhappy.

So there’s a good bit of sense in not risking going past a week.

The nose is a decent enough detector for most things, but in this case, the bacteria that are problematic can grow well before anything that will smell bad. Botulism ain’t stank, and that’s the one you have to worry about the most. Mind you, the risk is low. A lot of sauces are acidic enough that botulism isn’t going to grow well. I’d even say most. The other two risks are usually going to be less likely, because they have to get in by cross contamination of some kind, where botulinum can come in over the air (not likely, just possible).

Me? I’d chuck it out after a week unless I had a specific plan to use it soon after. I hate wasting food, but the truth is that pizza sauce is cheap and common. Nobody is losing out if a half a jar gets trashed. But that’s me, I don’t make pizza often. If you’re using it regularly, and only pouring out into a bowl or onto dough without dipping things in, you’ll use it up before it could hurt you, even if it’s a few weeks.

No bullshit, commercial canning is very good at killing nasties off. It’s only when we stick things into the container that risks start climbing to “oh shit” territory in a fridge.

3 to 5 days depending on whether you chilled it before first opening.

If it’s a can, first of all get out of the kitchen forever, and don’t save it.

I label it when i open it and i watch for mold growing on the top of the lid. This can range from 1-3 weeks

Is this a hypothetical or a need to know…soon kind a question?

Probably no more than 2 weeks. No mold, no weird smell and no weird taste.
Then boil it even before putting it on the pizza (bc I just feel better that way)

FYI you can freeze most sauces. So use what you need now and freeze the rest

1 week if just going to be heated, but a few days more if fully baked in another pizza

Does the can have any instructions? If not less than a week