Think of it like shoes.
You have to have sandals for breezy days. Maybe flip flops for days you just want quick in and out. You gotta have a nice structured shoe with good support for long walks. Maybe a hiking boot or shoe if you're into that. And of course you need some dressy shoes - you might have to compromise comfort.
Let me ask you - how often to your feet change size? Not often, right? So when you pick out a shoe, you know that it will work for you until it wears out, you get tired of it, or styles change (if you care about that sort of thing). But babies, well, they change! Oh, and so do new mamas - they (usually) shrink (eventually).
So the baby carrier that was ideal for the first few months may be awful when your baby hits six months. Or you may have lost so much weight that it isn't a good fit.
Newsflash! There is no penalty for getting another! And another! Yes, okay, they do cost money, but you can easily come by used baby carriers on Ebay, craigslist, the babywearing swap group, or thebabywearer.com. The latter, by the way, is the definitive site for all things babywearing. You will need to create a login but it's well worth it.
So go ahead. Buy a second baby carrier. Or even a third. Know that you can sell it and recoup some of your investment when the time comes.