How long does it usually take to become pregnant on Clomid?

Some get pregnant early in the clomid treatment, others it takes a few months. There is zero chance that you would be on it for years. It either works in the first few months (say, up to 6, with escalating doses), or it doesn’t, and then you are recommended to try more advanced options.

Like Shilolo said, it won’t take years. They’d never leave you on it that long.
Every woman’s body is different, it may work right away, or not at all. I’m not sure of the timeline of being on it, but I bet you’ll see results within a year. Oh and be prepared for multiples, as I’ve heard thats very common with Clomid! Have fun trying!!