A contract will ensure that there is no doubt as to what you require, when, for how long and for how much. Ask to see details of insurance, and equipment checks. Some bands play mainly at private and corporate events, where it will not be possible for you to see them perform. They should however always be willing and able to provide a demonstration tape. Ask for a live 'demo', rather than something produced in a studio - you want to hear what you'll get in real life!
Provide your musicians with full and clear directions with a map if necessary. They'll be more relaxed if able to get straight to you, and won't have the excuse to drop into a pub 'just to get directions' on the way!
Tell guests you are having a dance so they can bring suitable shoes. I'm always amazed at how adept ladies are at dancing in high heels, but they would probably welcome the information, and chance to pack alternative footware. In our modern society, this of course applies to the chaps as well. After all, we do play Brighton occasionally.
Check that your dance floor is safe, without holes or ridges to trip over, and is brushed out if necessary. Best to avoid the titchy little disco thingies with steep sides, they act more like a speed hump than a help. As a rough guide, we've found that eight square feet (NOT eight feet square) per dancer is a handy rule of thumb - although better to have guests a bit too packed (and not everyone tends to dance at the same time all evening), rather than rattling around i n a space that is too large.
Cable drums - please have a look at the maximum load they can handle, especially if only partly wound up. Try running a heavy load, such as heating, lighting or cooking, and they can heat up, even melting the insulating cable. If this happens, hopefully they'll short out before starting a fire, or burning someone.
Don't try to fit in too much in an event, particularly at a wedding where friends and family like to have time to talk with each other. A well-planned timetable will be able to cope with the almost inevitable over-runs.
It is usually fine to use our sound system for speeches, with either a microphone in a stand, or a radio mic. If the latter, would have to be at your risk – they are pretty expensive, and we’ve had users drop a couple over the years. We'll need to have a quick chat about using them (for example, tapping a ‘proper’ mic to see if it working is the equivalent of washing a classic car with sandpaper, and causes the same effect on the blood pressure of the owner).
You are the boss. If you want something, ask for it. 'He who pays the piper calls the tune'. Bands have their own ideas about what to play, and how to play it.
Do please take the time to discuss what you want with your group, and make sure you both have the same event in mind!