I work from my list and as I get one I start searching for the next one. Since everything on current list is Chanel flaps I get the one that's avail in my color profile that I have made for my flap bags
Somehow I think my bags choose me. A good example is my latest bargain find - a Mulberry Euston that I've been eyeing for years. I first saw one for sale on eBay but the price on it wasn't something I could justify.
Now, a well kept but much used Euston (for a price I could accept) popped up. It was on the national Mulberry fan club page on Facebook and the seller lives abt 2 km from where I live. So a quick PM and a few messages later we made a date last night, money and bag switched hands and now I'm completely smitten with my new Mully!
This has happened several times before; I set my heart on a bag but, as I never pay full price and am willing to wait/stalk for a long time, I sort of put my desire on hold and just let the bag come to me. The same with anything I'm wanting to buy; they always do.
So, it's more like I choose what bag will be mine at some point and then just let things happen.