The proposal itself shouldnt be a surprise, when it happens should.

Like, you should know they want to marry you before you do it. But the whole ceremony of a formal proposal can and should be left a surprise!

+1 - proposals never should be a surprise

I did have a friend who was proposed to with a placeholder ring. I think the jeweler sold the fiancé a ring and said he could come back/return it and have her pick out one she wants. That said, she preferred a diamond as opposed to an alternative so it was easier finding a jeweler that was accommodating.

Some people enjoy the surprise of when a proposal happens (as long as both parties are previously aligned on getting married).

Everyone’s got their preferences! Some people want the ring as a surprise and some would rather pick it out together, etc. And some are like my other friend, who wanted no proposal, picked out the ring herself, had her fiancé buy it, and called it a day!

I didn't know my fiance's ring size, surprise surprise she didn't know either, I got her friend to check it during the friends hens party. But overall if you're not oblivious, you should know if your other half wants the proposal.

Couldn't agree more. By the time you're ready to propose, not only should you already know their ring size, the other person should also be aware of your plans well in advance.

Springing a proposal on someone without discussing it with them beforehand is beyond fucked up.