Install the wood floor first. To the walls.
Then cabs.
Sometimes we can over think things. :)

I agree with Breezy. I thought about this too. I just could not wrap my brain around having nothing but concrete slab under my cabinets. It felt naked to me! To the wall, definitely.

We did a slightly modified approach. The floor guys came, did all the prep work on the floor (which in our case was extensive), then left. We installed plywood the same thickness as the floor under the cabs to raise them to finished floor height and then shimmed them level (BTW, floor guys prep floors to be flat, which is not the same as level. Your floor may still slope even though it's not bumpy. Getting a floor both flat and level is possible but unless there is a specific reason for doing that, it's not likely to be done). We installed the cabs and. then the floor guys came back and laid the floor up to the edge of the cabs.

Since we DIY'd the cabs, it didn't really affect the floor guy, as he did the prep work one week, we did the cabs over the weekend, then he did the floors the following week.

We installed the uppers before we started the floors, as it's much easier to work on them without the base cabs in the way, so all we had to do that one weekend was put in the base cabs.

That said, the good argument for putting them all the way to the wall is that if you ever remodel and want to move them, you might be sorry there is no floor below the cabs. In our case, we decided that was unlikely, the cabs are likely to outlive the floor.

I just went through this. This is what came away with.

If the floor is permanently affixed to the floor, like glue down cork or nailed down hardwood, it goes under the cabinets.

If the floor is floating, it should not go under cabinets as the cabinets act as a pinch point and prevent the movement of the floor that a floating floor allows for expansion. In that case, the cabinets would be put on plywood the same height as the flooring and the flooring would be installed to meet the plywood at the toe kick.

You may want to install flooring in the DW and fridge areas regardless, both to ensure they remain on the right level for moving if needed and for continuity as those areas may be exposed.

Now, I'm not a flooring expert by any stretch. But that made sense to me, so I went with it. My glue down cork is wall to wall.

I should also add, we did floor under our refrigerator for the reasons pointed out above but also put masonite under the fridge (on top of the floor) to protect the floor and if you have to pull the fridge out, you can put masonite down in front of it and roll the fridge out to a level surface.

Didn't floor the DW space, used plywood to get it to floor height and again masonite for easy sliding it out. Ditto the range.

So far very happy with that approach and feel it will let us easily protect the wood floors in the future if the appliances need to be moved out for any reason.

When our kitchen was remodeled with talked with our contractor about this. He felt that it was a waste of money to pay for labor and supplies to put the flooring under the cabinets and island. Flooring is porcelain tile and it was installed under the fridge and DW and slide in range. Because he was building our cabinets he created the boxes a little higher so the cabinet height would be just right once subfloor and tile was installed.

Thank you for the responses. This is the only issue I've dealt with where two different contractors keep trying to convince me the exact opposite conclusion. It does seem that, at least for hardwood, there is no right answer, just different points that may be more or less important for different people.

I decided to install floors first, mostly just to make my flooring guy's job a little bit easier. (Although if I did the opposite I'm sure everything would have been just fine.)