Yesterday I made up the usual yoghurt mix in my maker and while I was dating it I wondered how others date their fridge items.
If it’s stuff I’ve made like the yoghurt I just write the 2 weeks ahead date on some painters masking tape with a permanent marker, cut off at the appropriate size and stick on the side of the jar or the lid. That tape roll lasts for ages, rips off easily for a new date label next time, leaves no marks on the container and is pretty cheap. I use it for freezer dating as well. Use this same method for your opened pantry items as well.
If it’s a bought jar with a use by date already on it I will write the date I opened the jar on some masking tape or I will just write on the jar itself with a permanent marker to keep track of things.
For me this is the best way of not having or at least keeping down the amount of food wastage as you are not second guessing yourself on how long it’s been open or in the fridge for.