Dee, this is such a great question. My answer is mostly yes, and occasionally, no.
Most of the measures I take to keep shopping in check are not conscious or deliberate, if that makes sense. They are happy results of my ordinary shopping and editing strategy.
A few are more deliberate.
1. Regular seasonal editing -- this lets me know what I have, reminds me of various combinations, and also informs me of what I actually need so helps me create a sensible shopping list. This is not deliberate -- just the way I've always done things, and it does seem to keep me from buying stuff I already own.
2. Regular seasonal shopping. Except for special occasions, I tend to shop in two main periods -- late March-April, sometimes early May (for spring/ summer) and NAS or September/ October for fall. I used to shop in-person this way -- a couple of big city trips per year (when I lived outside the city) and/ or a few concentrated days of shopping when I lived in a larger city. Even these days, when a lot of my shopping tends to be online, I tend to concentrate it over a couple of ordering cycles. With exceptions, of course.
Keeping to specific shopping times means I just don't think of shopping outside those times. It automatically means I rarely shop at all between January and late March, in June, July (except for NAS if I do NAS) or August, or in November/ December. I don't have to set a no-shopping month because I'm not tempted to shop unless a genuine need presents itself.
3. Online shopping. I get most of my essentials and basics online and some other things as well. For some people, online is endless temptation, but I turn off notifications and send emails from stores to my junk mail -- so I only look at sales when I want to look at sales. Etc. I am sure I miss a ton of bargains but I don't care. If I don't need it, why look at it? This is one of my more deliberate strategies for curtailing shops.
The times when I'm most tempted and/or tend to go overboard on my shopping are the following:
1. It's time for a major wardrobe refresh/ rejig...and I can't figure out how to manage that or what to get to make it work. This happens most when silhouettes have substantially changed and I can't source what I am looking for easily and/or don't know what it is or how it is meant to fit. So about once per decade. I make more shopping mistakes and overbuy a bit. I don't figure out what is and isn't going to be a workhorse until after the fact. I did this last spring -- bought more than I needed, some of which didn't quite work out as I had hoped. (Silver jeans and silver knit dress, I am looking at you.) I do feel some guilt about this, of course -- but looking over my patterns across the years, I see it really is a once per decade cycle and perhaps goes along with aging, body changes, lifestyle changes etc. as well as the fashion cycle -- so I'm giving myself some grace on this.
2. I have a genunie need for an item and they have some kind of major sale on, two for one, that type of thing. I might buy the second item even if not strictly needed. It's not exactly sales-goggles because usually I can genuinely use the second item (it's a known brand)...and sometimes the second item turns out to be the bigger winner...but....
3. I am buying something online and. need to add something to get the free shipping. Ooops!
4. I am itching for change or I haven't had a wild card in a long long time. If that's the situation, I try to confine myself to thrifting and/or inexpensive stuff like accessories or summer tops.
