Well, after over a year of trial and error (and money), I have realized that you must select the bags that you want because you really love them not b/c of impulse or trend. How many and which designer is really a personal choice based upon what you like/your personality/wardrobe, etc. Different factors weigh in differently for each person.
Some designers just don't work for me (MK, all but one old LV which I own, Minkoff, DB, YSL, Bal, Jimmy Choo,Celine, Givenchy, Goyard, Proenza, Chloe, Dior, Burberry, all Bottega except for my card case, all but one or two Chanel bags-though I own Chanel wallets/yen holder, all but one or two Marc Jacob bags,
Fendi, Tods, Ferragamo, Valentino, MM, Hermes) even though I think that they are cute. They don't work because of style or too heavy.
I have 98% designer (non premier & premier) bags/wallets and 2 non designer python embossed lambskin clutch-wallets. I love them all. I change purses and wallets when the mood strikes- regardless of who made it.