I don't trust battery powered items for critical use. I wear a Seiko Orange Monster automatic winding divers watch daily and in the woods. Not cheap but no more expensive than the Suunto mentioned. Mine loses about a minute per month but is as tough as they come. Tells me what time it is and there's a couple of other features I could use but don't. Waterproof as any and no batteries. it's going on 3 years old and still looks great and works as well as it ever did.