The professionals you hire should have the following:
Membership of a professional association such as the Musician's Union
Public Liability Insurance such as that provided by Hencilla Canworth
Portable Appliance Testing (PAT) supplied by companies such as P&R
Bands that advertise themselves as a 'professional wedding band' or 'function band' will mostly fit in to one of the following categories:
Professional Wedding Bands
Professional bands comprise of reliable, highly experienced professional musicians. They have a broad, extensive repertoire, often featuring hundreds of songs, and are able to play a range of styles to suit the event. They will be able to adapt their performance to suit the taste of their clients, learn special requests and change the running order of a performance at a moment's notice if required. The small number of bands that are in this category maintain a very high standard of performance and presentation, and rarely play the same set twice. The personnel involved in this type of band would only expect to miss a performance in the most extreme circumstance, but should the need arise the band would always have the facility to book a stand-in or 'dep' musician, thus ensuring that the performance goes ahead as planned.
As is the case with most suppliers, it is common practice for pro bands to offer a 'Contract of Engagement' including the date, venue, timings, size of band etc. Most professional bands tend to be booked many months in advance and often secure bookings over a year ahead. It is wise to book early to secure the band that you want and always check availability even if you have left things a little late as even the most popular bands may have a gap in their diary.
Amateur or 'Pub' Bands
This type of band will predominantly play in pubs; this is often advertised on the 'Gigs' page of their website. The band members will usually have another line of work as their main income and generally consider their work in a band as a weekend hobby. They usually have a limited repertoire and often have to cancel bookings if they suffer illness, 'spilt-up', arrange holidays at short notice or have to take time off for their full-time work commitments.
This type of band will also have performances cancelled by diligent venue staff, when they discover that the essential public liability and electrical safety certificates are not place.
'Club' or 'Show' Bands
This type of band often performs in social clubs and holiday parks and usually has a very limited repertoire, ie. the same two x 45 minute sets, without variation for every performance. This limitation means that the performance cannot be personalised or adapted to suit the tastes of the client. Pre-recorded 'sequences' are often used by this type of band - some of the instruments you can hear are not being played live, as the band is 'playing over' a pre-recorded track. Some acts even mime to tracks, not making any attempt to perform the material live.