You can re-wear a suit several times as long as you don't spill on it, get it visibly dirty, super wrinkled or smelly, or sweat through it. It's actually bad to have a suit dry cleaned too often. It can break down the structure. It may sound gross, but your shirt, underwear, and socks are taking the biggest hit in terms of your body funk. The suit should remain more or less unscathed.

For a 1-week trip, you can probably get by with two suits, one pair of shoes (neutral, that go with both suits), and of course clean shirt/underwear/socks every day. With everything you pack, think about neutral colors and versatility. Pack shirts that will go with any suit, ties that will go with any shirt, etc. You want to have as many different combinations as possible. Or instead of suits, it could be two blazers and two pairs of pants, each of which works in tandem with the other items.

It may sound silly, but also think about whether anyone will be seeing you more than once during the trip. If the answer is no, you can get away with re-wearing more of your combinations, assuming they look and smell OK. If you'll be seeing anyone for multiple days, you should avoid repeats so they don't think you're a slob.