If you're tech-savvy make a paper wallet for every hundred bucks. Might be a zillion-dollar bill one day! If you are not, drop the next hundred into a hardware wallet. My Trezor is off-line and has a very slim plane of attack. Also, google "plane of attack" if you do not know the term. I use Shapeshift.io and my Trezor mostly, I used to use third parties but I do not leave much on an exchange. If I screw up my Trezor, Paper wallet, or silver stash, I at least know who too blame. I keep a few bucks on Coinbase for the credit card feature, a few bucks in my Mycelium sometimes, and keep my real money in my brain....