Here at Studio Europa, we always recommend that it’s better to install the hardwood floors (or any flooring) BEFORE you install the cabinets. Here are the reasons why:
Proper heights. First, it is important that the countertops are the standard 36” above the floor and that the appliances are at this same height so that if/when you want to change the appliances you will not have to rip up portions of the floor to remove it (your dishwasher could get trapped underneath the floor!). Of course, you could also achieve height consistency by inserting plywood underneath the cabinets, but this can cause other issues. As you still need to pay for the plywood and pay more for the labor, both in cutting the plywood and finer cuts on the hardwood around the cabinets, you really do not save any money.
Flexibility to change cabinet footprint later. Generally, the floors will outlast the cabinets. Cabinet styles and colors will come and go and over time they might need to be replaced. Solid hardwood floors may last for 100+ years. Sure, the color preferences may change, but the wood will often remain there through many kitchen renovations. It's important to have flooring throughout so that if you change the footprint of your cabinets, or decide to move the appliances, you have flexibility with the same flooring throughout the area.
Cleanest look. Installing your floor first will give you the cleanest look with the cabinets. This way, you don't need to worry about adding a quarter-round molding to the cabinets, and instead, you will see clean toe kicks that match the cabinets. The flooring just flows underneath the cabinets.
Safer on cabinets. Very importantly, you can avoid potential nicks or stains to your cabinets that could happen during the demo, installation, and/or sanding process of the floors. If this does happen, you may need to either replace the cabinet or just live with the damage. You will get a much cleaner look if the floors are done first. Below, see a full sequence of events to also account for minor damage that the cabinet contractors may cause on the floors. However, cabinet installers deal with a finished product day in and day out and are much more trained to install and move around gingerly. They will also put down a protective layer on the new floor.
One counterargument that doesn't hold water - what if you have water damage in your kitchen?
Some people might argue that it's "safer" to have plywood underneath the cabinets in case of a flood. They argue that this may avoid needing to rip up the cabinets if you have a flood. But if you do get water under the cabinets, the plywood would absorb the water anyway. Plus, you are more susceptible to having issues with the plywood which is untreated vs. flooring that is protected. Also, European cabinets would not get damaged in a flood since they are installed on 4” high adjustable plastic legs, a huge advantage!
Remember, if you do have water damage caused by a mechanical issue, insurance will often cover, or the warranty on the kitchen appliance.
How to sequence the hardwood floor refinishing with the cabinets:
Demo the cabinets
Demo the floor
Install the hardwood, sand with stain + 2 coats of poly
Install the cabinets
Install the countertops
Once installation is completed, add the final coat of finish. This helps to take care of minor scratches that may occur during the construction. Of course, cabinet installers must be careful, and they should allow for enough drying time before walking on the floor (ideally 4 days) and covering the floors.
The one exception is - Install floating floors AFTER the cabinets:
If you are installing a floating floor such as cork, vinyl, or laminate, you should install the flooring AFTER the cabinets. Floating floors are clicked together and not adhered to the floor. The reason for this is that floating floors move, and they expand and contract. If part of the floor is trapped underneath the heavy cabinets, it cannot properly move. This can cause all sorts of issues including bulging, buckling, and breaking. So, floors that are nailed (or glued) should be done wall to wall BEFORE the cabinets go in and floors that are floating should be installed AFTER and AROUND the cabinets.