A couple of things, at least until someone knowledgeable comes along.
Your suit won’t necessarily need dry cleaning every three wears - your shirts and underwear are what come in contact with the stinkier bits of your body, but they’re easy to change and wash. Your suit might need a pressing every three wears, but as long as you don’t spill anything on it, you could up that to every 6 to 10 wears without dry cleaning. Your mileage may well be different; it’s just that dry cleaning is harder on your suit, and a pressing usually does the trick. Make sure you’ve got a good place that doesn’t just puff the suits up with the steamer - that’s really hard on the fabric.
If you have to wear a suit daily, I’d say 5 suits is the minimum. (For the love of God, don’t wear the same suit on the same day of the week!) Some questions, though - does it have to be a suit, rather than a jacket & tie with dress pants? There’s a balance to be struck between budget and fashion - consider 20 suits at $200 vs. 5 suits at $800 vs. 2 suits at $2000. each. If the $200. suits were really of the same quality and gave the same positive impression as the $2000. suits, then you’re set. In my experience, it never works out that way. The suits from ‘Lotsa cheap suits’ look like cheap suits. The $2000. suits are usually of higher quality, and the places that sell them are supposed do a better job of tailoring, and of helping you put the package together. There’s some medium range stuff out there that requires some regular (eg weekly) shopping, and that’s probably the stuff you would be after to bulk up your collection beyond five. If I had to wear a suit every day, I think I’d try to be up around 7 - 10 suits, which gives you room for different seasons.
Above all, don’t forget that the shirt and tie can make the same suit look different, and they’re much cheaper.
I actually had a lot of fun the last time I went suit shopping. I went first thing in the morning, well dressed, and I cornered this fellow and explained exactly what I was after - a suit that was tasteful and elegant, but that stood out enough that it would get me remembered 2 years down the line by people who had only seen me for fifteen minutes. It was particularly fun that this was in Ottawa, where most of what this shop sold was bought by civil servants who want to look well dressed, yet anonymous. (I’m not in there ten minutes before this guy comes in and says “I have to be on television behind the Minister, but I need to be invisible. Invisible, got it?” My salesman laughed and said “That’s what my Mondays are usually like.”) I wanted the exact opposite. I also want the maximum versatility in a suit in terms of what shirt and tie I can wear with it. We had a blast, both picking out the suit, and then when it was back from the tailor that week, I had a little ‘party’ in the store, putting different shirts under the jacket and asking all the salesmen, one at a time, what would you put with it? They were selling stuff, no question, but it was fascinating to see how different people made the same suit look different with just a change of shirt and tie.