It totally depends on the horse and rider
There'a the 20 rule; if you buy a horse, it's age + your age = 20
Pretty good and safe rule, that's just for a minimum age... for example don't give a 7 year old a 12 year old gelding/mare.
It depends on the horse. As a general idea it is better to have a well balanced and experienced horse who can help the student grow and improve.
Greener horses are a possibility but quite risky.
I agree with them,but i think that before buying a horse you should try and try many horses, in this way you know how to behave with many kinds of horses. My horse was 7 when i bought him (last year) after two years of experience with other horses....
Depends on the horse I have met some really wonderful 5 and 6 year Olds as well as 10,15, to 20 year olds (-: if you want to find a good horse it is usually best to have a person with experience help you find one
I agree about 10 I was 11 but it also depends on how much experience you have! I had been riding for only 2 years but I was starting over small 2 foot fences when I got my first horse who was 13.
It depends on the rider's level. If it's a good amateur, I'd say a young horse, than you can school yourself, and know him from the beginning. If you have to learn many things yet, you should, as Melinda said, buy an older horse, like 10 years old, he'd be able to teach you what he already knows, and you'll be able to teach him as well :)
I'd say around 10 ... The horse is schooled, he knows already his job, and it permits, as a first horse to begin with a horse who can teach you! I think that's really important to don't make mistake to have a horse cool in his head :)