How often do miniture doberman pinchers go into heat?

Most females come into heat sometime after months, and then about every 6 months there after. By spaying the female at 4-6 months you miss all the hassle and risks of going through her heat cycle. An accidental breeding and a litter of unwanted puppies is not the worst consequence of failing to spay. Some of the problems are fatal.

I have a 10 month old mini dacshund, when should I expect her to go into heat?

Any time in the next month or 2. Try to get her spayed now. No we don't need you to go into breeding. We are already breeding enough dogs that we slaughter millions for lack of homes.

Dog's normally go into heat every 6 months and they are in heat for 3 weeks!:)