How often do you think of the complete collapse of civilization, be it from Zombies or otherwise, and do you already have a survival plan?
I think I'm in an unusual position. I have an engineering degree, I work in IT, and I write science fiction and horror.
I once took up a challenge to write a short story for every way the world could end off a science magazine list. I managed 10 stories out of their 12 different ways the world could end. A black hole going through the Earth doesn't leave much room for a story, just "We saw the flash of light until the ground collapsed into nothing, then grayness below us." In that regard, I think about it a lot, but as a hypothetical that turns into works of fiction.
A survival plan ... depends on what you consider a survival plan. I don't have a year's worth of food stocked up or the tons of stuff survivalist books suggest.
I do plan on emergencies as the government has suggested. I've been in a tornado. I've lived in a neighborhood where we were cut off from school and stores by floodwaters and ice for more than a week at a time. Stock up on stuff like that, and you don't have to fight to go to the store when the sleet makes driving inadvisable for days at a time. Or beg neighbors. Or eat oatmeal for the third time in two days because it is that or peanut butter sandwiches, since that's all that's left.
I once walked to the store to get more diapers and baby formula from the corner store. Slipping and sliding most of the way. Ice took down the satellite dish for processing payments. Because I had cash, I could walk out with bags of items, slipping and sliding all the way home. After that, we always stocked up on kid items so it wouldn't happen again. We don't have bars of gold, but always having enough cash to buy plenty of groceries or pay for essential services could be a life saver in bad situations.
We do have a variety of plans. What do you and the kids do if the house catches fire? What do you do if you can't come home? If the house burns down or floods, where will we go? We've made plans, because taking responsibility like this makes us better parents.