I never know if I should cut back my many perennials or not. Then I do, just because the garden looks neater, and I don't have to deal with all those mushy leaves in the spring... But I've read that not cutting back helps trap snow which acts as insulation against freezing/thawing.
And, when should it be done? If I wait until the leaves are brown, sometimes they are covered with snow!
Some of the flowers I have are: hosta, astilbe, bee balm, echinacea, black eyed susans, peony, coreopsis, ladys mantle, lavender, daylilies, iris, and many others.
What do you folks do in my zone?

I have a lot of the same flowers. I leave a few things for the birds to have the seed but I end up cutting most everything back. I pile mulched up leaves on everything to help with winter because there are so many good leaves right now. Then my beds are pre-mulched in spring. I try and keep the mulch off the tulips because they struggle through the mulch when it's still froze and their leaves get wrinkled.

I keep thinking I'll leave more cutting back for spring. Then I think about how much there is to do in spring and I like the idea of having one job at least already done.

I don't cut back but cover all of them with a lot of fallen leaves. In spring the leaves get raked off and added to compost. Sometimes I also add a layer of compost before the leaves are put down in fall. I haven't lost perennials in a few years but we'll see what happens this winter. I have one especially tender plant I am trying- almost zone 4 Japanese Anemone Robitussima (sp). I also cover the super tender stuff with cones or pots filled with leaves and turned upside down, then put a heavy rock on top.

I cut back most of the ones that look ugly -- I keep the ones that have nice fall color or have a seed head for the birds.
Some of my peonies get cut, some don't. Irises don't. I trim the lavender, but don't cut it all the way back. Black eyed susans and echinacea I cut. Daylilies, hostas and coreopsis I don't.

I rarely have problems with snow cover -- the beds by the sidewalk get all of that shoveled snow on it. The beds elsewhere get a nice bed of shredded leaves after the ground is frozen. I rarely loose any perennials -- in fact, most of my snapdragons make it through the winter.

Thanks for input. Just finished most of my cutting back today...did the iris, phlox, boltonia, and others. I used my hedge clippers and just cut up the leaves, stalks and tops and left it for mulch right in the garden. Hope I did the right thing. I may have lots of "volunteers" popping up in the spring! But that's what makes gardening interesting and fun.