I'll leave sauces and soups out overnight without worrying because they've been cooked for long periods of time and have a lid on.
But anything fresh especially salads and lightly cooked veggies I'll want in the fridge immediately, because those few hours out of the fridge make them limp and reduces their long term life.
But I'll happily open a container of leftover pasta that's been in the fridge 2 weeks! I know that wasn't the question but I'm dying to know how long people keep leftovers in the fridge. Vegan btw.
I didn't see anyone else mention this.... But take it easy on the dose on the first time.
I don't know how you're going to do it, but if you are making a classic "sandwich cone" (DMT sandwiched between 2 layers of tea or some other inactive stuff packed into a bong) then that DMT layer should be thin and just enough to fill the cone in a single layer.
If it's all piled up in a chunky stack and you smoke all of it then it's gonna be a helluva wild ride! The onset can be quite sudden and intense. Honestly it's part of the fun later on on your 2nd or 3rd times, but the feeling of being taken out of time and space can be quite jarring if you aren't expecting it!
If you don't have any hang ups about "letting go" and "giving in" to a trip then by all means go for more, but your question makes me think perhaps you might be best going slow on the first time.