Your osage bow should come with some sort of information in this regard (and good luck on your new bow!), but if it doesn't you might consider a few tips:
Osage is a very tough, hard wood, and can take quite a beating. The main enemy of your bow is moisture.
It should come with a good finish, tru-oil or something similar. If you're going to be shooting or hunting in wet conditions, a bit of common furniture wax will help keep the wood stable.
You might consider buying a "tip protector" if you lean the bow up against trees or walls out in the field.
Keep the string in good shape, and wax it frequently. The very worst enemy of a traditional bow is a broken string; it can cause limb failure.
Some weeks back, I encountered a fellow at my local range with a bow such as you describe. He was even older than me...
![Smiley Smiley](https://slinging.org/forum/yabbfiles/Templates/Forum/yabb21/smiley.gif)
His bow was some 25 years old, and still shooting just fine.