Planning
The honest answer depends on your guest count, venue layout, and how many events you're covering — here's how to actually figure it out.

A single photographer works well for smaller, intimate events — a single-day ceremony with a modest guest list, or a pre-wedding/engagement shoot where there's no need to cover multiple simultaneous angles.
The limitation is simple: one photographer can only be in one place at a time. If the bride is getting ready in one room while the groom's baraat is arriving outside, a single photographer will always miss one side.
For any wedding with simultaneous events happening in different locations — bride and groom getting ready separately, a large venue with a mandap far from the guest seating, or a reception with both a stage and a dance floor — two photographers covering different angles at once captures far more of the actual day.
Multi-day weddings (Mehendi, Sangeet, Haldi, Wedding, Reception as separate events) generally need a team rather than one person, simply because of the sheer number of hours and distinct moments across several days.
Videography typically needs its own dedicated person or team — a photographer switching between stills and video mid-event usually means missing shots on both. If you want a cinematic film in addition to photos, budget for a separate videographer (or a combined photo+video team) rather than expecting one person to do both well simultaneously.