I suppose this is one of those opinions you should keep to yourself but since it's on topic.
My biggest gripe is no mater how museum quality your uniform looks what makes your impression is if you look like a soldier of the period. Of coarse this is a pretty unrealistic and impossible for some to do but if your old or over weight no matter how much time you put into your uniform you simple do not look like somebody of the period which I think is more important than how you wear your gear or it's construction.
Actually, I was having a discussion about this with my father the other day. You could be a lard-ass with amazing paperwork and a Grade A first person impression and know the language you're using very well conversationally and have the finest dirty wool money can buy... but to anyone else you don't look like the soldier you're trying to portray. You're a fatbody in a uniform and you look hilarious when you sit down to take your hit or take a knee instead of going to prone because you may not be able to pick yourself up again.
One of these days I'm going to get too old to realistically portray a regular soldier of the time period and I'll have to pick up another duty - Volksturm for example. Something I see too often are guys who go, "Yeah, I'm too old to be in the line anymore, so I'll become an officer." and it fucks everything up with top-heavy units. It's ridiculous seeing a full Battalion command staff and then 25 guys in the line. I could go on and on about why ACW isn't as fun as it used to be and is dying. Also, why WWI and WWII is booming.
--
In regards to buying junk at first and then slowly replacing it - well, there's merit and detriment to that. Sure you can get all the gear you need right away, but you're buying absolute crap that will fall apart on you and your impression will look like shit. You don't dress up to look at yourself all day or you'd have to carry a large mirror with you everywhere you went. You look good for everyone else around you. People notice good impressions. It makes them go, "Damn, that guy looks great." and it inspires them to perform better.
For example, my father and I running through the woods with our combat impression being very nearly 1:1 with how they did it back then whipped all the other units in our area into shape and its starting to have a domino effect. Leading by example is very real and also very fun. Who doesn't like getting complimented on their historical costume and looking the part?
Back on the main topic, is that if plenty of people go the easy way and buy shit at first, that's a lot of shit being bought. That's why you'll go down to the Sutlers and there's Paki uniforms and cheap leathers and tin fucking EVERYWHERE. It's because there's a market for it and it drowns out the sales of people who sell more quality items that are just a little bit more expensive. This isn't unique to ACW either. It's honestly something to think about when you're bringing in someone who doesn't know jack shit about reenacting and is essentially trusting you with his purchases.