Hi there and a warm welcome to our forum, I'm sure you will get some good info from here!
Not heard of the practise of stripping the lower leaves off, maybe I missed that one? How old is your plant, if it's relatively young it will still have all it's leaves, even low ones. You will find that as the plants age they will naturaly shed the oldest ones, so leaving the bare trunk you may be seeing in our pictures. I would personally not remove them especially as it's growing well for you. Neither would I transplant it at the moment unless it's in a soil that is not draining fast, ie is peaty and holds water too much as that can cause rot esp in colder months. By the sound of it your soil is not a problem as it's doing well, I would wait till things warm up. Hope someone else chimes in with their opinion.
Gill from the UK.

I agree with Gill. The leaves all the way up the trunk is good. I would not remove anything and if they fall off, then so be it.
I would follow what Gill has mentioned.
Rick

I don't think that anyone strips the lower foliage. As the caudex develops and the plant gets bigger the new growth is further away from the base so it might just appear that the plants were stripped of foliage. More foliage is good, it's more food production for the plant.

Glad to see some similar thoughts coming in!
Any chance of a pic of your plant please? We like to see pics and they can also help tremendously in answering lots of queeries.
Gill from the UK.

I might be able to shine some light on the semi-defoliation you're seeing on the plants this time of year. During the winter, mine are indoors under a T12 fluorescent shop light, and they tend to go dormant. When they do that (at least in my experience), they will drop some, if not all, of their leaves. Changes in the light it receives (i.e. moving the plant from a full-sun area to a shaded area, moving the plant from outdoors to under artificial light) can also cause them to do this. All of mine are pretty much fully defoliated right now, except for the very top leaves.

Thanks for all the input. I'll post a picture of my plant asap.

Here is a recent photo. When should I transplant?

Thank you for the picture. Don't do anything until spring.
It is good looking now and hope it will do well for you next summer.
Marie.