| In my case, a double dose of Lantus would be horrible...25 units doubled to 50 units...not a good thing. I fight low days even with 25 units and have to cut back.
I've had the odd occasion where I forgot if I'd taken my morning dose (and only dose)...I have gone so far as to wait about 5 hours to see if I'm going sky high...or not...I would never take a second dose...did that and worried all day (needlessly, it turned out)...
It mostly happens when I get up super early or when my morning routine gets turned upside down. A sticky notepad in my insulin box is good for jotting down a checkmark for the date...I need to go back to that routine the older (fuzzier?) I get! | 
