Once I took my fast acting instead of my basal which was a huge dose for me- lovely people at tu D talked me through that one, some oj and food got me through that mistake. And once I took my basal instead of a bolus, I called my endo and they just said to test a lot, for some reason, it seemed to make no difference at all to my body that day, I have no idea why, lol!
People here I think told me to put a rubber band on the basal pen which I always do now and I think to myself before injecting, is the the basal and feel for the rubber band each time. You have to try not to be distracted at all when you inject.
I don't think I have ever injected twice, but I often forget right after I inject if I injected or not, lol!
My novopen echo records your last dose for you which is good for both basal and bolus because sometimes I bolus and then think, how much did I take? lol. Usually I record it in my phone on the ibg star app right away though so I can look back and see. I don't know why all the pens aren't made this way, also with a date/time etc. The novopen echo has a little clock with sections filled in as time passes to tell you how long ago the dose was but I think a specific time would be better.