I am not sure of your question, but normally even with framless cabinets (especially where the walls may not be perfect), a 1" filler is used against the wall. There are 2 reasons for this. One, it's easy to adjust for the imperfection in the walls because this 1" piece can be trimmed as needed. But also, it gets the cabinet away from the wall to allow for door or drawer opening.

Thanks, that makes sense, but I should add more detail: The 2 ends of this wall will have corner wall and base cabinets and continue around the U shape. Also, according to the cabinet company :"the hinge allows the door to open 125 degrees, but when open 90 degrees the door remains within the cabinet width". This comes into play at one end of the U where we would have a wall cabinet against the refrigerator - the door should still open 90 degrees fine without a filler between the wall cabinet and refrigerator, right? Or am I not understanding something about this?

coupla things.

Ccoombs1 is referring to starter molding where the front of the cabinet is against a wall. If you use starter molding, there is enough room for the cabinet door PLUS the handle to open without potential binding on the wall or having the handle drill a hole in the wall.

For the corner filler thing, the cabinets you use in the corner don't matter. The distance between the two walls at various heights and the straightness/flatness/squareness of the wall at the base of the u matter.

If the walls are off by even a small amount - the two ends slant towards each other slightly, OR the top of the u isn't square, the cabinets in the "U" need to become slightly longer or shorter in order to have the corner cabinets in the right place. Every wall is off a bit.

If you do the demo now of your existing kitchen, fix the walls and then test for squareness, you could order the exact widths needed. But without doing that first, you need to order a filler and intend to make your run 1.5" to three inches shorter than you believe you have.

The cabinet-ref thing is because the cabinet will open wider. So when you open it - you'll forget and just open it. Either your hand or the cabinet door or handle will smack into the ref. Also, the cabinet company may not be allowing for the knobs or handles that you'll choose being on the cabinet door. Sometimes, you can specify the direction the door opens and avoid this. Sometimes, you need to get a little door stop to prevent the door from opening more than 90 degrees.

Anytime a cabinet is up against a deeper thing like a *hood*, ref, cabinet pulled forward or made deeper, oven cabinet, this can be an issue.

If you have any handle or knob the door may not open even to 90 degrees. You will need to subtract the depth of the knob/handle on both the door you are opening and on any door/drawer at right angles. Filler is usual in these places for this reason.

Also...don't worry about how the filler will look. On the end of a run, it is not noticable. If you had a run of framless cabinets with a piece of filler stuck in the middle somewhere, you would notice it, but even that isn't as bad as you might imagine it would be. Trust me! I had to use filler on the top cabinets so there would be a place to end the crown and it looks perfectly fine. You can see it here, between these two top cabinets. Poor planning on my part...it didn not occur to me that there would be no place for the end of the crown to go since the cabinets were at different heights. I didn't want to abandon the idea of crown, so I came up with this. Filler is not such a bad thing!