Short answer: I ONLY buy when I not only love a bag, but can't imagine not owning it. I never buy "like" bags. Not even for functional uses.
Long answer: My bag purchases go through a bit of a different process than just like or love. 5-7 years ago, I had over 100 bags. Almost none that were quite right. (I only have one of them left.) Having gotten sick of the constant buying and frustrated with never feeling satisfied, I decided to purge. But, I also needed a better way to buy.
After a lot of stumbles and missteps I came to my current approach. I keep an Evernote of all my bags on my phone. Every time I get dressed I chose a bag. If I have one I love that's great for my outfit, it gets a tick mark. If I don't, I make a note of what I needed (pastel shoulder bag, black crossbody, etc.).
When a "need" gets a lot of tick marks (usually 5 or so within 3-6 months), I start hunting and buy the bag I fall madly / crazy / over the moon in love with that meets that need! 😍
Now, I never, ever buy bags I just like. And I've ended up with bags (currently 25, I may buy 3-4 more) that I'm INSANELY in love with and fit my wardrobe and lifestyle. 😊👜👍