I am still a little afraid of missing something if I forget that, as my father snobbishly suggested, and I snobbishly repeat, a sense of the fundamental decencies is parcelled out unequally at birth.
And don't forget to bring a warm jacket, you may think you won't need one in this warm summer weather, but remember that evenings in the mountains can get quite cold.
So native speakers often forget which one gets an apostrophe. Does the possessive get an apostrophe or not? So no. The possessive form does not take an apostrophe here.
Small but essential: Don't forget a flashlight or headlight, batteries, a lighter (for a campfire), a first aid kit, bug repellent, sunscreen, and extra clothing.