I don't know if it rises to the level of "most", but whenever I email, or speak on the phone to a potential customer it's all about "qualifying" the seriousness of the inquiry in the first email, or first minutes of the conversation.
Despite having pricing for some basic services right on my website, I still get inquiries as to "ballpark, how much $$?".
Without getting into the weeds, recently had a "customer" send me his rifle for rebarreling, along with stock, scope, etc.
Trade emails for days trying to finalize the scope and pricing. Then, he goes off into left field and thinks he'd rather leave the one he sent alone- and go for a new custom build. Kick around another half-dozen emails over a few days on that one.
Then, he starts sending me links to factory rifles he's interested in...
Trying to keep the "customer" happy, I explain I'm not a retail sales operation- but I'd be happy to order whatever rifle he wants and have it shipped to his FFL.
Ultimately, after several weeks of emails and phone calls, he emails "Sorry I've changed my mind constantly, never mind, can you ship my stuff back?"
Probably a couple hours of my time, between emails and phone calls. Unpacking, sorting, labeling and logging in his "stuff"- which was so horrendously packed when it was shipped that the box was trashed in transit. Re-pack all into packaging I supplied, then pay to ship it back to him. Sent it all back on my dime- didn't even care to ask him to reimburse the postage.
Yes, this was an extreme case. Most often, things work out fine- but be mindful that if you come across as a "tire-kicker", it'll likely be a very brief interaction.