substituting resistors

I'm looking for a replacement resistor, but can't find one with the exact specifications.

If the required resistor has a tolerance of 1%, and a substitute needs to be found, would the tolerance of choice be 0.1% or 5%?

Hazel.

Better (smaller percentage) tolerance resistor will always work where a less precise one is desired. The inverse usually not so, but it depends on the actual circuit - sometimes there's really no need for a precise resistor, but the author of the schematic put it there for reasons known to him alone. You can try and use a 5% resistor and you might get away with it. You can also substitute it for a potentiometer and fine-tune the resistance manually with an ohmmeter.

Thanks Eenleth,
I didn't know what the "tolerance" was - tolerance to what? But nw I know it's about the given resistance rating of the resistor, so it all begins to make sense.
I'll go for the 0.1%, then - available in fewer numbers (I don't want 1000 of them!)

Cheers,
Hazel.

It's about production error tolerance, to be exact. That's why you're going to pay more a piece per 0.1% - in a resistor factory, they make a batch of, say, a million resistors which are tested at the end of the line and sorted according to how close they are to the expected value, and there isn't going to be many resistors in that batch that fall into the 0.1% range. Don't be surprised if a few of those costs as much as a thousand of 5% ones.

Hi, thanks.
I have checked all my costs - generally the more expensive ones come in 10s or 25s, the cheaper ones come in 100s or 1000s. For my choices,25 more expensive ones come to less than 1000 cheaper ones, so I'm going with those. Thanks for all your input. I've since been reading about resistors/ratings/tolerances on Wikipedia and Instructables, of all places!
Cheers,
Hazel.