Should I assign rooms to all dwarves in Dwarf Fortress?

I usually make a lot of three-square rooms with a bed and a chest each in my fortresses, and declare the rooms bedrooms. Sometimes dwarves seem to assign themselves to beds and put stuff into chests, but this happens quite seldom.

What is the proper way of managing rooms for my dwarves?

Solution 1:

Dwarves will seek to claim an unclaimed room when they look for a bed. There's two practical ways this scenario resolves:

Scenario A - Assigned Bedroom

• You manually assign the Dwarf a bedroom
• The dwarf goes to the bedroom when tired

Scenario B - No Assigned Bedroom

• You have not assigned a tired Dwarf a bedroom.
• The dwarf finds the nearest un-claimed bedroom and claims it.
• The dwarf is now assigned this bedroom, and will hereafter follow scenario A

Scenario C - No Available Bedrooms

• You have no bedrooms available
• the dwarf finds the nearest open bed and falls asleep.
• it is possible that they sleep in an owned bed, but they seem to prefer going to a dormitory or barracks before they sleep in an owned bed or just fall asleep in the dirt.

Note: sleeping outside of a proper bedroom will not increase a dwarf's happiness, and may decrease it if they are forced to sleep on the floor. Nobles may also throw a tantrum if a lower noble or a commoner has a nicer (bed)room, so it may be wise to assign them the most opulent space available.

So in general, you don't need to worry about assigning dwarves bedrooms manually - as long as you have unclaimed bedrooms available, they will seek them out as needed.

One final note: Dwarven families share beds and bedrooms.