To Change the Site or Not To Change the Site

I'm an insulin miser. I love getting every last unit out of a cartridge, and I hate to change it when there's more than a couple units left. Grace only uses about 12 units/day so a couple of units left in her pump can last a long time.

I also hate to change Grace's site at bedtime. New, cold insulin seems to pack a punch, and usually leads to her numbers dropping.

This all leads me to last night...
Scene: Grace's bedroom
Time: 8:30pm, bedtime

Me: Grace has 3 units left. She should make it through the night, right?

Chris: Yeah, she should be fine. That is, unless we need to correct her in the middle of the night for the pizza.

Me: She's 81 now. So even if she goes up she's got room. And she ate the pizza, like, 2 1/2 hours ago.

Chris: She'll make it. No problem.

Cut to my wonderful husband, taking on the overnight checks -
11p - BG 224
2a - BG 257

Scene: my bedroom
Time: 5am

Grace: Mama, my pump is beeping. I don't have any insulin left.

Me: (indecipherable grumbling as I make my way downstairs to get her supplies for a site change)

5:15a - BG 100
7:15a - BG 62

... on second thought, maybe that new, cold insulin would've help with the overnight pizza high!