There are 3 methods to address the issue;

Have the cabinets installed on top of the floor.

Place 1x4 on the floor in the exact cabinet footprint.

Have the cabinets made with a 5" toe-kick instead of the standard 4."

Using the plastic composite non-compressive type shims, shim your cabinet bottoms to the finish floor height, plumb, level and in plane with each other.

I've always put the cabinets on top of the finished floor (typically hardwood). This has paid off hugely in avoided aggravation when we've moved cabinets around later on. Paying for a few extra feet of flooring material is trivial compared to the savings in not having to patch the floor later on when things change. As an added bonus, it's much easier to sand and finish the floor without the cabinets in the way.

Thanks for all the great responses. It's good to know from the variety of answers that there are many different ways to do it right (though I know that doesn't mean aren't many MORE ways to do it wrong :-).

Another thing I've always wondered about with shims and EZ-levellers is that it would seem to concentrate the weight of the cabinets, counters, and contents into just a few spots vs. distributing the weight equally along the floor. Given that everyone uses some sort of shim, that technique must work fine, but it seems like it would make it more likely that some parts of the floor (those further away from a joist) would sink more over time than those directly over a joist. And it would put more stress on the cabinet (though if it's well-built that shouldn't be a problem).

To make the cabinets fit together as smoothly possible, I was thinking I could join a run of three cabinets together (to each other) before installation. I've seen that suggested in forums and DIY videos. But if I do that, it doesn't seem like 4 shims/levellers at the 4 corners would be enough - the center cabinet would effectively be floating. But trying to shim that assembly at 8 points would be awfully tricky. Any thoughts on that?

You are correct in stating that the quality of the cabinet boxes is important and should be a concern at time of discovery.

Instead of the style of doors and drawers.

Since the strength of the cabinet boxes is at the outside or perimeter of the box, thats typically where the shims are placed, under.

Multiple base cabinets, combined into a unit can be difficult to adjust and maneuver.

With Mediterranean cabinets, they are typically clamped and screwed together within the box, in a sequence.

Standard cabinets, with face frames, are clamped at the face frame and screwed together through the face frame and commonly hidden behind the hinges,
They are then also joined at the front and back, along the top of the boxes, with shins which maintain a consistent separation, front to back, as well as a straight line installation, along the total length of the installation.

beautybutdebtfree:

Excellent link. Thanks.

We used pieces of the flooring we were going to use to raise the cabinets up. We were putting reclaimed hardwood down, but didn't have it all pulled up from its original location yet while we redid the kitchen. We were able to get pieces of it though to set the cabinets on as shims in the meantime.