The combadges provide precise tracking and identity for the computer to keep track of coupled with biometric scanning. Life forms are tracked individually and crew signals associated with their badges.

Outsiders do have to break in and are shown to often be frustrated by the computer denying access. Given that alongside LCARS being ridiculously modular - helm can have full engineering/weapons/sensors access, for example - and it kinda makes sense that an individual bridge crew member wouldn't need to login again every 90 seconds because they didn't touch their console.

Anyone assigned a station likely has their access codes keyed to their combadge along with their preferences for their LCARS settings.

As to the announcing self destruct codes another user mentioned in another comment, my headcanon is that these are rotating codes distributed on a per-shift basis to be used as the final emergency confirmation in case such a need should arise. Voice print and matching shift code both are required from two commanding officers.

Picard literally explains this to the capitalist the bring back from the dead in season 1

My understanding is that tanks don't have locks or keys. The theory is that in an emergency you don't want your weapons neutralized while someone tries to remember where they left their keychain.

I can imagine a starship working this way. In fact, during The Neutral Zone Picard basically says as much:

RALPH: If they are so important, why don't they need an executive key?

PICARD: Aboard a starship, that is not necessary. We are all capable of exercising self-discipline. Now, you will refrain from using them.

Yes, but then we wouldn't have an episode. Click that link from your bank. Have an adventure.

Some of them DO require you to yell your password out in a crowded room. Usually just the really important ones though, like the self destruct.

Seriously though. I always just assumed the computers were smart enough to track every person and just knew who was using them based on constant sensor data. No password required because it already knew who you were and if you had access.