Oil Dates, If a cooking oil has never been open how long past the “Use by date” would be acceptable

It is absolutely OK to filter and reuse deep-fry oil.

It's not uncommon at some short-order restaurants for them to filter the oil daily and only change it once a week. Of course, it does start to taste a little "off" when you reuse it that many times.

There's also the matter of impurities lowering the smoke point; even when you filter, the result is obviously not "pure" oil; the more you reuse it, the lower the smoke point gets, and eventually it will actually start to smoke at deep-fry temperatures (i.e. become unusable).

For home use, I'd recommend no more than 3 or 4 reuses. Check the oil to see if it needs to be changed sooner than that - if the colour or smell is off, don't use it again. Best to compare it against a sample of the same "fresh" oil; sometimes it's hard to just eyeball it without a frame of reference. If it looks totally clear and smells fresh, you could probably go up to 5 or 6 reuses - but definitely not more than that.

_{P.S. There will be some people who tell you that you should never reuse oil for general health (not safety) reasons. My response to that tends to be that if you're eating deep-fried food, you're probably not all that concerned about long-term health risks. Rest assured that if you do a lot of eating out, you've eaten plenty of food fried in "leftover" oil.}

I would do it the other way round, I'd fry the sausages first, then add the veg. This has a few benefits as I see it:-

• The sausages will brown more evenly, purely aesthetic but some people will think they are not cooked if they are not brown.
• You'll get the oil out of the sausages so you'll have a better idea of how much oil to add when you add the veg, if any.
• The veg will sweat down in the sausage oil which is likely to be much nicer than the other oil
• You can cook the sausages on a really low heat to start with so that they really get sticky and caramelised, then when you add the veg back in you can add a spoon of water/vinegar/stock to deglaze the pan an get that lovely sticky sausage goodness all over your veggies, which will be delicious.

You could optionally take the cooked sausages out of the pan and do the veg separately, or keep 'em in there, I'd probably take them out so I could turn the heat up a bit without having to worry about the sausages.

I'd say that when you do add the veg you want a thin (1mm ish) layer of oil in the pan. Depending on the pan this is probably a tables spoon or 2. You probably don't need to scale up as if you are cooking a bigger batch you will probably use a bigger pan, and so a similar depth of oil should suffice. If you are using the same pan, but with a deeper amount of veg, then I would add a little more, but I would make the depth of oil in the pan proportional to the depth of veggies.

Remember the golden rule. You can always add, you can never take away. And once the veg start to cook down and the volume decreases then the oil ratio will be higher, so start out with a little less than you think, just enough to coat the veg when tossed in it.