The old saying goes, "The poor man pays twice". Or maybe more fitting for the modern sound man, "Save up and buy your second one first."
Now that the adages are out there let's get down to what that means. People coming up in the business ask those more seasoned about gear all the time. Let's set aside people that show up in the forums looking for a 10 kw system with a digital front end but they only have a budget that won't even buy a decent pair of pole speakers. This isn't for the clueless, it's for the people who have it together and are really trying to make a good investment in their gear.
Don't fall in to the trap of buying something "just to get things going". Those purchases tend to become permanent fixtures and then you're left operating with an inferior piece of gear on a long term basis. Unless you need something right this minute to get through a gig, hold off on the impulse buying. Do your research, save your money and make a good purchase.
Here's an example. You need a DI for your rig. You can go out and get something from ProCo or Whirlwind for under $80 and that will probably serve you well. But sound systems are getting better all the time and a fully featured DI with great specs will not only serve you well but probably generate some good will with the clients when they see you setting out the good stuff. So is it worth it shelling out $200 for a Radial? Probably. Especially if that's what you really want and/or need in the first place. Why pay twice?
OK, maybe the DI example isn't great because who hasn't reached into the bottom of the box to pull out that old Whirlwind Imp in a pinch. Let's up the ante and talk about consoles. Do you really need to get a twenty-four channel console if all you mix is bar bands? Probably not. But if you have hopes of ever doing anything larger it's a real good idea to weigh the benefits.
Divide it up by cost per channel if you need to. If sixteen is going to cost you say $800 bucks, that's $50 per channel. To go to twenty-four you're looking at $1200 so that's still $50 per channel. Worth saving up the money from a couple more gigs before you invest? Probably. Otherwise you're looking at selling off a used console that's now worth a lot less, or having an $800 investment that sits around. Again, not that having a spare around is a bad idea.
Think these things through before you buy. It's simple math to add up the cost of a place holder plus the thing you really want. If that piece of place holder gear isn't going to serve any purpose once you have the "good one", then don't buy it. Buy your second one first Brethren of the Knob and Fader.