Personally I leave most of mine until early/mid spring.

I only remove the parts of perennials now that have collapsed due to rain /wind damage

There are several reasons for this.

1. Cutting everything back leaves the garden looking bare

2. Perennials with frost/snow on them can look lovely in winter

3. The less hardy ones benifot from a blanket of old leaves stems to act as wind /frost protection

4. leaving stems on gives cover for overwintering insects and small mammals + the seed heads are a source of food for winter

Thank you very much for this and it makes such sound sense.
I shall therefore just tidy up droopy plants and those that look very bedraggled.

If there are any that could hide our 'friends' the snails and slugs, I cut them back, as well as mildew-y Phlox. I leave most cutting back until the early spring for the reasons that Anchorman gave you.

I did that yesterday,Chris..just tidyed up,and cut some back ,but not down to the ground..agree with all the above,it's better to do it in spring...

I sometimes reduce the taller ones by half but leave the others for the reasons given.

I have done both, not sure which I prefer though, as the previous posters have said it does benefit some creatures to leave them uncut but it depends how you like to see your garden, tidy or untidy, I am never sure. As I said I have done it both ways, it all depends for me on how much interesting foliage is left about, this year, in the borders, it seems that they have quite a lot of lovely seed heads hanging around. The late sunshine has helped them maintain their stature and the colours are very pretty. I am tempted to cut back but at the moment I am hanging in there and leaving all the interesting plant structures for a later day. But after saying that if it does start to look too untidy I shall be out there with my secateurs (weather permitting) - I am a sunshine gardener. I like the sun on my back the old bones do not like the cold months.

Ps. I find that things are easier to tidy up after a cold spell too.

Your advice has been most welcome and I have a much clearer idea on what to do because of sound, sensible reasons.

Thank you very much indeed for taking the time and trouble to help me with this.

I shall try to hold back with those secateurs for a bit longer!