Sorry M-o-N, but I'm a bit tired of making this point on this forum, so if I come across as a bit jaded it's because, well because I'm a bit jaded....getting 2 would enable me to weed out the possible ridiculous first quote (way to high or way to cheep).
I don't think that people will ever stop taking part in what seems to me to be as ridiculous a circus as dancing girls walking on big spheres and clowns throwing buckets of confetti. The whole concept of multiple quoting is based on the [false] premise that you can spot the cowboy amongst the indians, but if they're all cowboys then you're stuffed from the beginning.
In which case you simply deploy the principle of vicarious trust..."And I say get one estimate from one tradesperson/company that you trust. "
A lot of people do not know such a person and resort to the internet asking imposable questions.
Step 1: Ask friends, relatives, colleagues and neighbours to recommend someone whom they've personally used and would be happy to use again.
Step 2: Engage that person to do the work.
Step 3: Pay them what they ask for.
Oh I know, your eyes are popping out at the idea of paying without bartering, but just imagine if the only people doing any work had to be recommended because of their previously good work and fair pricing. Those whose work was too poor or prices too high would immediately stop getting custom. Easy innit!