I let Maia go through 2 heats before I finally got her spayed. I had thought about breeding her. If I could go back I would have gotten her spayed at 6 months before any heats. Here is a list of my non breeder, basic dog knowledge on why I would get females spayed before first heat.
1. No messy bloody nastiness
2. No increased nipple size, Maia's nipples are big now
3. No messy bloody nastiness
4. No risk of accidental Litter
5. No PMS's female
6. No swollen vagina which looks nasty
7. No messy bloody nastiness
8. No smelly and I mean smelly dog before, during and after heat cycle
9. No increased health risks
10. No unwanted and unneeded attention from male dogs
11. No risk of mood or character changes in your female
12. No messy bloody nastiness
13. No change in your normal daily routine
1. Cheaper spay when younger because she weighs less
2. Easier spay when younger because not so much fat build up
3. Easier, quicker recovery because she is younger
Just some of my opinions