Do people have to get their hip replacements replaced?

Sometimes: Hip replacements typically last at least 10 years, and as long as 25 + years. There is always a chance that the replaced hip loosens, wears out, gets infected, or has other mechanical problems which require a future revision.

Yes, occasionally: If the implant wears out, the entire implant or a part of the implant can be redone. Revisions or redos are also done if there is a problem such as instability, infection, fracture or other problems.