I tried to get three quotes in once for a new combi boiler and nine radiators; a complete heating system.
Being a fair sort of bloke, I told each plumber that I would be getting three quotes in when I phoned them up.
1st Plumber said he wasn't interested as I'd just go for the cheapest quote.
2nd and 3rd Plumbers said they'd call and gave me dates and times.
In the end only one plumber turned up, he quoted and got the job.
I learnt from that, because in the past when someone phoned up and told me they were getting in three quotes, I never bothered to quote because I assumed some 'muppet' would go in cheap, so it wasn't worth my time.
And since then, for a factory unit, I was the only window cleaner out of three to be asked to turn up and quote; and I got the job at a nice price.