If you've been in the remodeling industry for a number of years, this won't be news. However, if you are a normal human, I'm going to address the issue and ramifications of counter top height.
Since we do so many remodels, we are often asked to try and save an existing backsplash. Mostly, we replace formica counters with stone counters. A 'normal' base cabinet is 34.5 inches tall. A 'normal' finished counter height is 36 inches tall. The typical method to prep for formica is to strip out the tops of the cabinets with 1X2's. These are placed around the perimeter of the cabinets and across the tops of the bulkheads of the cabinets. Then, a sheet of 3/4" plywood is placed on top of the furring strips. Then a 1X2 band board is place around the outside perimeter of the cabinets, nailed into the side of the 3/4" plywood. This covers the 1X2 furring strips. Formica is then glued to the top of the plywood and glued to the face of the band board. The top intersection edge is usually beveled so you get that black line that runs around the edge of the cabinets. The backsplash is then placed on top of the formica. Usually, it is tile.
When replacement time comes, here is what you are faced with: 2cm, 3cm or 4cm [laminated] granite tops. 2cm=3/4". 3cm=1 and 1/8". 4cm is two pieces of 2cm glued together. Be mindful that 2cm may actually be 11/16" or it could be 7/8". It depends on who produced it. The same variables apply to 3cm.
So, if you are wanting to save your backsplash, remember it is going to start at 36" off the floor. Once the formica is stripped off, your base cabinet is going to be 34.5" off the floor. So, if you use 2cm or 3cm, there is going to be a gap somewhere. Either on the bottom of the granite, or between the top of the new counter and the existing tile backs.
If you do 4cm, you can re-strip the cabinets with 1X2 furring strips and the laminated edge will cover the furring strips. The counter height should match the existing tile, or within a caulkable margin. The problem here is two-fold. One, you must 'handle' the material about 5 times to get a tight lamination. It is not a matter of simply gluing a secondary piece on the bottom and calling it good. Thus, with all the additional handling, the costs go up.
The second problem is grain match. As people's tastes in stone continue to get more sophisticated, they tend to like unique stone with movement. If all your cabinets are straight runs, no big deal. We can make the grain match. Got any funky angles, big round corners, want the top grains to match properly? Big problems. With any of these conditions, something has to give. And what 'gives' is grain match. So, if the grain match is no big deal to you, this solution will work. However, most of our clients expect it to be right [as do we], so lets go back to 2cm or 3cm.
Furr up the tops to meet the backsplash and run a piece of wood trim under the tops to hide the height variation. This works.
Leave the counters on top of the cabinets and run a piece of tile trim or stone trim to cover the void between the counters and backsplash. This works.
Now, lets look at economics. I'm going to use some 'average' numbers. Let's say you are putting in some very nice 3cm granite. Let's say it will cost $4000. The average backsplash will cost [labor and material] about $350. Am I going to go into contortions trying to save the $350 component? Economically, no.
There are always variables, and if you have individual questions, I'll be happy to answer them, but this should give you a basic overview of some considerations you might want to ponder. No one likes expensive surprises. We would be included in that group.