I'll be flamed alive for this but I went on a sunbed for 5 mins the day before going on my week-long beach hol this summer.
Benefits were twofold - firstly I felt more bikini-confident (cellulite loads less visible if brown somehow!) and secondly I was less likely to get burnt in my first few days as once you have a bit of sun on your skin you won't burn as easily - true tale.
If you haven't used a sunbed before, 5 mins is pretty short but enough to give a bit of colour, perhaps the amount you'd get after a couple of days of being careful in a hot country and much more even.
My mum is a fairly disapproving lady of most things I do but she said it was a sensible plan - better to use sunbed and prevent actual proper burning, which is the main factor in dangerous sun exposure. She was prescribed a sunbed for her house after having bas eczema-type problems and is no longer typically middle-class judgeypants about them.
Anyway it worked and I managed to get a steady, reasonable tan over a week's hol without burning at all, wearing factor 20 when properly sunbathing, and always on my face even if just sight-seeing etc.
Sunning yourself really is the new smoking - socially unacceptable, and not half as bad for you!