Agreed that if for nothing else, putting the cover panels on top and bottom will keep spacing aligned. Otherwise you have to account for that 1/2 inch on either side in some other way.

You need some wiggle room to get your range in and out. Mine has 30 1/2" between the base cabs. With two 1/2" panels on the top there's 31". You cannot see a difference. If you add the panels to the bottom they still will not be identical since you need required clearance for the range.

In the 4 Ikea kitchens I've gone, I have not added panels on the sides of the range. It's a different story if they're needed as filler but entirely unnecessary.

We left exactly 30 inches in our ikea kitchen, as the range was slightly under. In fact, it's under enough that there is about 1/16 inch gap on one side and 1/8 on the other. I can't imagine having a 1/2 inch gap on either side. That would get so messy!!

It really depends on your range, so be sure to study the specs. My range Is a slide in and is exactly 30", not less. The distance we allowed between countertops is 30 1/16", but between cabs and range there is about 1/4". In the install I'm just completing, the distance between countertops is 30" and the range is 29 3/4.

The question about the side panels is a personal one if you have the space, and if you think it will look better.

Here's a pic of my range without the side panels.

I am using an existing range for now, to be replaced later. But these things "should" be replaceable without tearing out the cabinets and counter! I see bbtrix has a slide in, which IMO is not designed to be easily replaceable and specs should be carefully reviewed. I did check specs on a few brands of freestanding ranges, and most are just a tad under 30" wide. GE says theirs are exactly 30" but the install diagrams say the opening should be a MINIMUM of 30". So I guess they expect a 30" range to fit in a 30" opening. Tight fit for sure!

I allowed room to add the side panels in my design. But if I don't I will just center the range opening under the center of the cabinet over the range. The fact that the wall cabinet sides won't line up exactly with the base cabinet sides is never going to be noticeable. On the end of the run, the side overhang of the countertop typically extends out past the base cabinet anyway. That might even make the backsplash line up on the at end, right?

To be safe, I may allow 1/8" extra space but think a wider opening would collect gunk, and make it more likely that the sides would be visible (and should therefore be covered with a panel).