With proper care, your bowl should last for years. They come free of defects like knots and cracks.
Perhaps the biggest enemy of wood is sudden changes in temperature and humidity. This means if you leave your bowl in a car on a hot sunny day, the high temperatures in the car can make it crack. Same with leaving it in the car or garage during Oregon's cool wet weather for a day or three, then taking it into the house where it is warm and dry. Allow the bowl to acclimate by putting it inside a paper bag for a day or so, and away from drafts and direct sun light.
DO NOT put in the dishwasher. The joke here is that they can go through, but only once. This is the sudden change in temperatures and humidity thing again, which causes cracks.
DO NOT put them in the microwave. They can actually catch fire.
DO NOT use them for storing food inside the refrigerator. The refrigerator is a dehydrator, and wet food inside the wood bowl, and drying on the outside of the bowl will create stress and cracking.
Your bowls come finished with a walnut oil and carnuba wax (vegetable type wax) product from The Doctor's Woodshop www.doctorswoodshop.com. I consider this to be the best bowl oil available. Care and feeding (oiling) of your bowl has many different schools of thought. Some never treat or put any thing on their bowls other than what comes from the foods that they eat. Some wash with soap and water every time they use their bowl, and oil every time they wash. There does not seem to be any one agreed upon method for taking care of your bowl.
However, here are a few of my personal observations:
Washing: Most of the time, I just rinse my bowl out with water, and use a plastic scrubby pad, or one of the Scotch Brite type pads. If the bowl starts to look a little dry, then I will put more oil on it. This is maybe 2 or 3 times a year. I use my bowl a couple of times a week.
Different oils: For protection, walnut oil is probably the best product available. This type of nut oil will cure and harden, offers great protection, and is food safe. It takes a week or so for it to totally cure. It needs fresh air, and some UV light. DO NOT place in a window sill as that can expose it to too much heat. Reflected UV light is fine. The walnut oil you buy at the grocery store, usually does not cure, or if it does, it is at a much slower rate. This comes from the way the oil is processed. The bowl oil will cure and harden, giving good protection, but the store oil generally will not. The Doctor explains it better on his web site.
Your vegetable oils will not cure and harden. While they can be used to keep your bowls looking nice, they can create problems. This comes mostly from build up on the wood. Since the oil doesn't cure and harden, any extra that is left after eating, or oiling, if left on the surface can go sour. To prevent this, make sure to wipe off all surface oils. Some times this will include food particles as well.
Most of the other commercial bowl and butcher block finishes are mineral oil, and some times they have some bees wax in them. They do make the bowl look nice for a few days, then the finish is gone. At best it offers minimal protection.
Washing: As I said before, every one does this differently. Do at least rinse out after each use, and wipe dry. If you wash, do not soak the bowl in water. Get it wet, rinse and scrub, then it can drip dry or you can towel dry it.
Soap / No Soap: Absolutely, if you can feel some food and oil build up, you need to wash the extra off. Hand dish washing detergent is fine. Apply it directly to the bowl if there is a lot of build up, or just plain dish water is fine. Scrub and rinse off. If you do not want to use soap, you can use a wedge of lemon or lime (citrus juice) and some table salt. Combined, they make a good emulsifier and disinfectant mix. Rinse off, and dry.
If you should forget and leave your bowl in the water over night, at the very least, the bowl will warp. To prevent it from stressing and cracking as it dries, place it in a big paper bag, and put it some where out of any wind or sun light, but do not enclose in a plastic bag or tub. It will dry out back to normal in a few days. If you try to dry it back out too fast, it may crack.
Stains: What ever you put into your bowl will soak in a little bit. Wood is like a sponge, and will absorb what ever is in it. This happens even with a finish on the wood. Blueberries will leave a nice purple color, as will other berries. The stains don't come out, and we refer to this as 'seasoning' or 'developing' character.
Storage: Wood bowls need to be able to breathe. They need fresh air. If you put them away in a plastic bag, or tub that is mostly sealed, they can develop mold and / or mildew. This type of stain can be difficult or impossible to remove. Cardboard boxes are much better.