We're a reasonable sized builders, at this time of year we see a lot of people speculating as to cost/possibility of work who are looking for advise or an estimate for works. I would advise you are very clear that you are ready to carry out the works and not just speculating. Ask for a quote and the lead time worst case scenario.
It can take several days of work putting together a quote for an extension, or a bathroom refurb etc when you factor in survey, correspondence, material research, checking into the legal side of planning etc and what might be needed. We have 4 this week we are working on so I am one man down on site all week as he is estimating/surveying and I am putting together final quotes and researching lead times etc. If none of our domestic home-owners come through we have lost two people for a whole week with no finance coming in to cover (We will be paying wages but have to ensure our live jobs are coming in on budget). If we see leads that imply a client is just speculating, or you approach in that manner you may find that we turn down the opportunity, this way we ensure we're not reducing our capabilities onsite to chase work that has a limited likelihood of being agreed.
We also find that people expect quotes within a few days, but we have to do all of the above plus run live sites, maintain the books and wages, eat dinner, not always work through the evening and weekend. I would advise that a fairly busy but smallish company offering domestic works need a week or so to put together a full quote. A lot of the builders are squeezing in a site during the day, surveys in the evenings/weekends and any admin/finances etc where they can. Clearly if its a small job this may not be the case.
Rated people - you pay a fee for each lead you buy, the home owners estimate seems to determine how much you pay. I would say 99% of the leads I have seen this week are people considering works and wanting advise - or an estimate, which isn't a proper quote its just an abouts figure to gauge if you can afford the work.
My builder - you pay a fee if your short-listed by the home owner. This seems to have larger jobs, rated people seems to be more handymen etc. (In our area)
We would never miss appointments, that's plain rude. We are mainly commercial though so our client base is 90% repeat and we are well known for our client attention. We rarely advertise, we operate almost entirely on word of mouth or repeat custom. Definitely look to see if any neighbours have had works and can recommend a local builder, or of your work place has work done the team may carry out domestic too.