The only con is leaving the vanity in place and tiling around it. You know the right answer, so do it.

Sorry I have to question and over think everything! I want to make sure we do this right. So - what if we (or future resident) needs to/wants to replace the floor years from now? Is the tile just chipped away around the edge of the vanity since it runs underneath? Or does the whole vanity then have to be removed and everything repaired? sorry I just don't know what's considered the best order for installations.

We're not doing an open bottom vanity (ugh dirt traps!) so that's not an issue of needing tile run all the way under. It's more a timing issue with I can get Tile Guy to do this in 2 weeks but Whole Package Guy is running about 2 months into projects. Then I can have a floor and toilet functional while we figure out the rest. But if it's better for future floor replacement to just tile up to the new vanity then I'll just have to make a decision.

Yes this kind of stuff paralyzes me! I'm bugging you all and not my husband :)

ok I read some more on this and they explained you are used to seeing the tile butt up to the vanity because of cost. As a builder building hundreds of homes w 2-3 baths each that's a lot of unseen costly tile that they don't want to pay for so the tile up to vanity is the standard builder option.

I'm always devil's advocate.

If I choose to tile the whole floor: what if i need/want to replace the floor later. If I choose to tile up to the vanity: what if I choose to replace the vanity later?

I can never win. Also in reality the fact of either one of these things happening is pretty slim and not my problem w a new owner (it's all tasteful neutrals).

Think I'll go with the entire floor.

The bathroom in our first house still had the original tile. It was over sixty years old at that point. Newish vanity. Second house still had original tile. It was over fifty years old at that point. We replaced the vanity, which was obviously not the original so it was on at least the third vanity. Tile flooring lasts longer than vanities. Tile under the vanity.

And vanities are easier to remove/replace than flooring.

For generic tile and a generic layout? I recommend tiling the entire floor.

Now, if you were using a very expensive tile and to tile under the vanity would require you buying another box? Or two more boxes? That might be a reason for cutting in.

It can also depend on design. I'll often run a border around the room, sometimes the design will result in the border running around front of the vanity too.

When in doubt, tile the entire floor.