cowboydoc has done a great job of explaining the costs. If I were at home I could bring up Quicken and tell you exactly how much we spent on our horses for the past 10 years.
Other items to consider;
1. Do not underestimate is the amount of work, and therefore the amount of time, caring for horses requires. Cleaning stalls, getting supplies, barn maintenance, being there when the vet is, being there when the farrier is, etc. My wife always wanted horses and she does a fantastic job caring for them, training them, etc., (I take care of the supplies and maintenance) but I think she underestimated how much time they take. When you add horse maintenance time to horse enjoying time it can be quite a bit and sometimes does not leave time for much else. Other things that don't get done around the house because of the time devoted to the horses can contribute to the frustration/tension level.
2. Much like a dairy farmer, horses need daily care even when you're on vacation and you can't load them in to a carrier and take them to the kennel /w3tcompact/icons/smile.gif.
3. It's amazing how relatives and friends will want to ride your horses. When you thought you were going to spend a lazy Sunday afternoon reading and snoozing, the phone rings, "Can we come out and ride in an hour?" We have actually had friends get upset when we sold a horse they considered 'theirs'. They had made what they thought was a generous offer, pay the vet and farrier bills if we kept her. Hello? Where would they be in August when it's hot, humid and we're loading hay? Where would they be when, in the middle of winter, when one of the horses pulls a water pipe out of the ground and flood the barn?
4. As cowboydoc mentioned, vet bills are the hardest to predict. Horse throws a shoe, steps on one of the nails, call the vet AND call the farrier. Upset stomach, not eating and not drinking water. Mix up a batch of molasses and PeptoBismal tablets and stay up late walking the horse so he doesn't lay down. Odd infection that drains for over a year. Horse is limping, nothing obvious, vet brings portable x-ray machine. Cha-ching?
5. Caring for the tack, buying blankets, etc. You will get a whole new batch of catalogs in your mailbox containing things someone just has to buy.
Again, please don't take these comments as negative. We have met a lot of very nice people because of our horses, not the least of which are the people on TBN. The horses have taught the kids discipline and helped them mature plus numerous other benefits.
However, I compare owning horses to an iceberg. What people can see, e.g., barn, riding, etc. is about 15% of all the work associated with owning a horse. I used to wonder why boarding fees were so high. Now I know /w3tcompact/icons/smile.gif