system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why is it that people spend hundreds to thousands on engagement rings? won't they just be replaced by the wedding ring in a couple month anyway?
gpt
They aren't replaced. People generally wear both (with the engagement ring being the flashier one, and the wedding ring being a relatively plain band. Still can be rather pricy depending on what material/finish/etc).

There's a whole history to why, but the simplified version is that people used to treat 'being engaged' as being enough to act married because there was often a very long gap between deciding to get married and actually being able to have the ceremony. Sex, living together, etc. Some sort of big gift was a sign that the guy was actually taking this seriously rather than just looking for a way to get laid, and if it fell through at least the woman would be left with something more than syphilis.