We did it on one side of the kitchen where there is room. We pulled out the cabinets about 2" to make sure the american DW would fit with the custom panel (I heard a few horror stories and we had a brick wall behind it). Our cabinets were regular depth but the extra counter space is great. I wished that I made the uppers 2" deeper too. If you have a side panel next to an aisle or open space, that too will have to be bigger to accommodate the deeper lowers. In my next kitchen (ha ha) I will pull out the lowers 3".

If I had room I would have done it in other areas too.

I did that on one side of my kitchen and absolutely LOVE the extra depth. I had the lower cabinets installed 3" from the wall, so no extra depth inside the drawers, just extra counter space. I have 2 upper cabinets above that space and I ordered them 3 " deeper and that extra upper space is also wonderful. It is a very simple way to increase usable space and I learned about it HERE! Really happy about BOTH of those useful tips.

I have 30" everywhere and would never have less....love it.

We are having the counters on one side 27" deep, i.e. 3" deeper than standard. Our base cabinets are the standard 24" deep, and we pulled them out 3" from the wall. And don't forget that your granite overhang will add an additional 1-1/4" or so. We don't have them installed yet, but we are anticipating more roomy countertops. Our coffee maker, toaster, etc., won't be crowding the counter workspace either. Also, we have a Kitchenaid dishwasher. The Kitchenaid DW's tend to stick out a little, not be flush with 24" deep cabinets. But it won't be a problem for us cause our cabinets are pulled out.

Furthermore, our uppers will be 15" deep, i.e. also 3" deeper than standard. I have seen a number of threads on this forum complaining of 12" deep uppers that don't fit their dishes or platters. Won't be a problem with our 15" uppers.

Our kitchen is small, which is why we are doing the deeper counters on only one side.

Here are a couple more threads for you to read:

Thread about Base Cabinets Depth

Thread about Upper Cabinets Depth

Oops, I just realized one of my linked threads above is about shallower-than-standard cabinets! So I'll link another one about deeper counters:

Thread about 30" deep counters

You don't need extra-deep base cabinets ... and the plumbers and electricians will LOVE having that space to run p[ipes and cables.

My sister has a mix of regular and extra-deep counters and it's creat. She has the most-used things at the back of the counter, which still leaves room to work or pull an appliance forward.

She's regretting not having "refrigerator-depth counters all over the kitchen.