I'm contemplating obtaining a physical bitcoin QR code address such as this idea:
http://imgur.com/a/dHSCB
or this commercially available process:
http://www.plaquemaker.com/Titanium/Titanium-Tags.html

Before I pull the trigger on one of these kinds of solutions, I need to better understand how to use the address correctly.  My understanding is that when BTC is used from an address, then the address should not be used anymore for security reasons.  If that is the case, then using a single address to receive funds is confusing to me.

I prefer to use Coinbase to handle my spending BTCs.  If I use a single address to receive funds within Coinbase, and that money is spent later, will the original address still be safe to use?  Will Coinbase automatically handle that address safety?

Are there any other considerations I should understand before I spend money making a physical QR code address?

Thanks