How many times have I worn it in the last 6 months?
I always use 6 months as a benchmark, as in England, you've probably had it through most weather conditions. Unless it's really summery or holiday wear, you've probably had the chance to wear it in that time.
A good trick to measure this, is to turn all of your hangers the same way around. Each time you wear an item, switch the hanger around. Then, at the end of the 6 months, if there are any pieces still facing the original way, i.e, you haven't worn them, it's probably about time to get rid! The chances of you wearing this again are probably rather slim!
Is it 'fast fashion', or is it a staple item I'll still be wearing next year... and the year after that, and the year after that?
Up until recently, I've always been one to buy ~a lot~ of stuff. But it was always the cheap stuff. In my head, a lot of cheaper things were often better than a few, select, more-expensive-but-better things. Lol. I wish I could go back and show my younger self how wrong I was.
I much prefer buying staple items for my wardrobe now. Yes, they're normally a little more expensive. but I also tend to get a lot more wear out of them, and I'll keep them for much longer, meaning I don't have to keep buying a whole new wardrobe every season!
Will the quality last?
I guess this is very similar to the point above, but buying less, higher quality items, normally works out cheaper in the long run! So whenever I'm having a clear out of my clothes, if there's things that were cheap to buy, or you can just tell probably won't last, they're the first to go!
How many other items does this go with? How versatile is it?
One of the main principles of simplifying your wardrobe, is figuring out which pieces are the most versatile.
Which ones can you wear the most? Which ones can you dress up and dress down? Which pieces go with ~everything~?
Sticking with these items in your wardrobe will mean that you'll need a lot less, but you can still mix and match and create some fabulous and exciting outfits.
Am I only keeping it for it's sentimental value?
If you ask any of my family of friends, I'm one of the most sentimental people ever. I find having clear outs really hard because I just want to keep everything, particularly if it has a memory attached to it.
The solution? Take a photo of it.
This way, you can still keep it for the memories, but it's not taking up space in your wardrobe, or sitting there unworn for months...or years, in my case.