Is it worth getting a second opinion on a repair quote or just a waste of time?

I've been quoted for what feels like a fairly major repair and something about the number doesn't sit right with me, but I can't tell if that's genuine instinct or just the shock of the bill. I know people say you should always get a second opinion on big jobs, but I've also found that the second opinion is often just a different guess, and then you're left more confused than before. I came across https://www.800sayara.com/ while trying to figure out whether a second quote is standard practice, but I'd rather hear how others handle this. Do you always get a second quote on expensive repairs, or only when something feels off? And how do you decide which opinion to trust when they contradict each other?