Hi Laura -- I wanted to comment on this post some time ago. The thing is I couldn't put find the words. I just know when it is time to purge something. It is like that item is a "weight" around my neck and I want it gone.
There could be any number of reasons why an item is purged: changing life style, itchiness, too loose, too tight, bad color, too short, too long, neckline wrong, sleeves wrong. Once I consciously (or unconsciously) decide I don't like something I will never wear it again. I could store it away hoping I will change my mind, but history has shown me that I never change my mind. I only pay to have something cleaned and I store it away for what a season? a year? two years? The timeframe doesn't matter. When I come across that item again, I dislike it as much as when it was first put away. Then I always ask myself why I paid to have it cleaned/pressed just to get rid of it. Crazy.
Now, the issues of "money spent" and/or "in perfectly good condition" and/or "I might regret getting rid of this" are considerations I had to overcome in purging. It took me a while to make peace with the "money spent." Mistakes happen. Why keep something I don't like or wear just because I already bought it? Why wear something that is uncomfortable when I have so many other comfortable "me" pieces in the house?
"In perfectly good condition" just means that someone at the Goodwill will get a great deal on something I hope they will enjoy much more than me.
"I might regret getting rid of this" is a bit harder for me. I find things that are on sale (SCORE) and the perfect color, but they are a bit too short or a bit boxy. They hang in my closet because I just might one day want to wear it to some unnamed event. And the color really is so perfect, I may never in a million years find this exact color again. I have a few of these items in my closet (unworn, cleaned, and pressed).
I purge throughout the year. I do major purges at the end of each season as I evaluate and pack away for the new season. Then I bring out all the items that had been packed away. This is usually when I feel the most frustration. WHY did I keep this piece? I hated it when I put it away. I hate it just as much today? I immediately purge it regardless of whether I have found a replacement. The truth is that I probably don't want a replacement of that item or it is such a common item that it can easily be replaced. I speak specifically of black knit tops.
Some people would say I am a ruthless purger.