The shortest honest answer is: it depends entirely on what you would mourn if it were not preserved.
Every couple should hire a photographer. The single frame is the longest-lived artefact of a wedding, and there is no substitute for it. Beyond that, the question becomes more personal.
If you want to hear the room again
Hire a videographer. Voice, music, the timbre of your grandmother laughing — none of these are in a photograph. A film is the only place the sound of the day will ever live.
If you want the day back tomorrow
Hire a content creator. Your photographer's edit takes months. Your videographer's edit takes longer. Neither studio is built to deliver overnight, and asking them to is asking them to compromise the long work that is the reason you hired them.
A content creator's only deliverable is the morning after — beautifully edited footage that lets you and your families re-enter the day while it is still real.
If you can only choose two
Choose a photographer and a content creator. The combination gives you the heirloom layer for the future, and the experience layer for the morning after. The film can sometimes come later as an anniversary commission.
The right question is never how many people to hire. It is which parts of the day you would be devastated to lose.