None. My first selfbow.is a little whip ended but still shoots 15 years later. Second, third, etc were tillered better and none broke. All of my first bows were osage staves. My first yew, ash, hickory, hhb all still shoot. Again, they were staves I cut and seaskned. I didn't break one until I started getting really carried away with using 2nd and 3rd rate woods, and worse, and pushing limits of design.. Had an Arborvitae explode the first time I drew it by hand, and I had a couple cherry and walnut bows chrysal on me due to poor design.
I've made a bunch of bows with 'boards' I made from staves/trees I cut, but never messed with boards from home improvement stores.
You should post pictures as you progress with your next bow so these guys can guide you through design and tillering. Lots of knowledge and experience here to 'draw' on. Keep at it. It'll come.