Nothing can really hurt your granite. Some colors MAY show some oil staining if not sealed, but granite is much sturdier than marble, which can easily stain. I've had my granite counters for 13 years. They are a mottled golden brown agains my unstained cherry cabinets. My husband does use some sealer about twice a year and purchases it from Lowes or HomeDepot.

No need to test the marble. I'll tell you right now-- unless it's a serpentine marble (usually dark green with lightning bolt type veining to it), it needs a sealer. As for recommendations, one of two-- Miracle's 511 Impregnator, or Stone Tech Impregnator Pro, and yes, it's very easy to seal. Take an old towel or cotton t-shirt and cut it in half. Use one side to wipe the sealer on. Let it set for about 5 minutes or so, and then take the other half and buff off the excess. Easy as pie, but time consuming, so you could really save yourself some money doing it yourself.

You must live where it is warm. A laundry room in our garage would freeze, pipes would burst, and it would be a homeowners nightmare. Start planning for your laundry room, utility room / mud room. Seriously, start clipping your ideas together for your dream laundry room one day. Or maybe add on to your space. I know I get crazy with ideas but it is good to dream it keeps us TKO people healthy. If you have kids, dogs, messy husbands (oooooh that s was freudian) relatives that pop in to visit, and football players with muddy cleats. You NEEEEEED a mud room. a tiny room about 4 by 4 can be a great place to get the shoes off, coats hung, dog leash put away, back packs stored, why even a little shelf to charge cell phones, a message board, and yes tucked in a closet your laundry machines. The tinest of spaces can be made into a really cool utility/laundry/mud space. Okay let me see while I am thinking about this we were talking about floor cleaning.. Yes, a drain in the center of the floor. When you wash the floors the dirty waters goes down the drain. And if the laundry machine overflows... who cares it goes down the drain. The possibilities are neverending... Don't get me started. I will start thinking about a laundry room for your place and then Plllog, Buehl, Rhome, Remodelfl, Jterrilynn, palimpsest, judydel, sandyponder, bmorepanic, florantha, breezygirl, dianolo....there are far better GW minds on this space who could magically create your dream laundry room off your kitchen. Have a super day. You must be tired now reading my endless note. ~boxer

If you do need to seal--and I actually don't think you do--this is a 5-minute job that does not require your contractor to come back to do. It does not need any special skill - if you are able to wipe lightly in a circular motion, you can do it. In fact, if your counter is the type to need annual resealing, you will have to do this yourself eventually anyway. Buy the smallest bottle of sealer you can find at HD. It will still outlast you in this kitchen, as you just need a very small amount in order to seal. (Don't get one that says "enhancer", you just want "impregnator"). Follow the directions on the container. Seriously, 5 minutes or really 3. It'll take longer to clear your counters of your toaster etc than it will to seal. Having said all that, I am not sure you need to seal. There is such a thing as too much sealant, and/or sealant applied when it is not needed. When that occurs, your counters will show what is called "hazing" as the sealer sits on top and doesn't absorb, either because there is already sealant applied, or because the stone is so dense it doesn't need sealer (I haven't sealed my granite counter in years because it is a dense-type stone). One way to tell if you have hazing if you aren't sure is to drag lightly a dish or bowl on the counter, and if it leaves track marks, your sealer is not needed and hasn't absorbed. That could be what the "swirly marks" you mentioned are, but we can't tell without photos. The drag marks are in the sealer layer, not in the stone. You can remove it with acetone; there are threads about this. http://www.homedepot.com/p/Miracle-Sealants-16-oz-511-Impregnator-511-PT-SG-H/100672948