Reassuring re:insurance, however I prefer to deal with as few parties as possible, so while insurance is a good measure, I'd rather not deal with a claim. Plus, I don't want anyone to have my keys except myself, and possibly family, etc.,. So an exchange that stores my security info sounds like it may be good for some people, I'd rather avoid that.
So, it sounds like I should only use coinbase as an exchange only at this point, and store offline... I'll look into that.
Why sell the bitcoin after the client pays? Keep it!

I would recommend this: get a bitcoin wallets app on your phone such as blockchain.info, or coinbase and you can ask your clients if they want to pay in bitcoin after the job. If they do, simply open the wallet on your phone and shoe thrm your qr code to one of your addresses.