My personal preference is to give the mare a year off between breedings, or even longer in todays economy, but I'm pretty much not the norm for breeders. I'm also very critical of what I produce and if the stallion's confo isn't stellar I won't use him regardless of temper or color. He's to be the whole package or I'm not interested. Same for the mare. I know people who breed mares that I would have shot long ago because they are such witches, and produce the same, but they feel they are 'too valuable'.
I have 3 stallions and they all "understand" that if they don't behave or challenge me one time too many, they will be geldings, I don't care how good they are. My life would be a lot easier if I'd geld them all and not bother with this breeding business, and at some point I may do just that.
As for being under saddle, especially with the economy the way it is, I think we owe it to our mares to get them under saddle and at least started in some discipline. If something happens to me or she becomes sterile and needs to be sold, then she stands a chance of having a nice person pick her up for a riding horse rather than automatically getting sent to slaughter as a used up broodie. Again, IMO, only. I have 2 mares left to start and that will be this year while they have the year off from breeding.
All this of course, is just how I feel about things, not what everyone else agrees with.