I'm usually pretty impulsive, or at least I used to be when I focused more on sub $100 knives. Now, I may do a bit more planning. I dont generally have 400 or 500 bucks just hanging around to spend.
My last four $100+ purchases were a mixture:
My local knife shop ran an add that they were a Microtech dealer last October. There is no way I would pay the prices they command without handling one first. Tried an Ultratech and was sold. I had a fee bucks socked away so I just bought it.
Last November I finally bought my first CRK. It was a reward I promised myself for reaching a hard earned goal. Just a basic PJ Inkosi I bought from Spark's shop. Hasn't left my pocket in a year. Worth every penny.
Next I stumbled across a review of a Combat Troodon. This was during the more hard-core shutdown in the spring. I have the number of the Local Knife Shop's owner, so I just texted him to see if he had one. He did, gave me a price, and we met safely for me to buy it from him using my stimulus money. Not a bad way to blow 500 bucks

Big fan.
Finally, I just purchased a Kershaw Lucha at the LGS. Went in looking to buy some ammo. Didn't find any, but saw that balisong under the glass. $120? Why not.