I do that all the time. Never had a problem. If it still looks good and usable to you, go ahead and use it. I usually mix in some new compost and a shaky-shake of slow release plant feed granules.

No, its not absolutely essential, though there is a small risk - but the really critical thing is whether what was growing in it before had any kind of disease, infection or infestation. Fungal disease particularly is a reason to avoid reusing it.

Agree with Bamboo, not absolutely essential but we always do to be on the safe side.

When growing Petunias or Madagascar Periwinkle, here in the desert, we always empty the pot, scrub it out, and let it bake in the sun for a week before planting either in the same pot. There is a fungus that kills both, and stays over in the soil for years. Other plants don't require the same precautions.

Pansies with downy mildew would be a case for renewing compost, and sterilising the container here. Though sterilising by sunlight is just a lovely dream here, unfortunately!

Yep, boiling water for porous pots, or bleach water for non-porous, for you folks. :)

Replacing all the compost is easy for small containers but its usually safe to just replace some of it for big ones as long as you check for nasties.

I wasn't referring to disease infected plants or pots riddled with fungus or mildew. The answer to that is obvious.

Easy to miss a cutworm or a few vine weevil eggs though?

If you never it, the worms & eggs are probably not there. Of course there's no blanket answer for every situation, you'll have to use your best judgement.

Agree Stera. easy to miss something and kick yourself later...

When I first experienced our local fungus, a couple of plants died in a big pot, and I thought nothing of it. Then, next year, neither plant worked at all!

What is left in the pot no matter what the size is usually very compacted and netted with thin roots. Don't give up, few minutes more effort will give you an empty pot to wash out and what you have removed can be well broken up and then mixed into fresh compost.

Gardening in the UK is quite different experience. I reuse potting mix all the time and never ever had a single problem. All my plants are vibrant & healthy - no hiding eggs or wevils lurking around.

Yes Bathgate gardening in the UK IS a very different experience... thus we advise folk on what we in the UK do not what you in the US do!

There you go Mary. Use your own judgement about the state of the compost before deciding.