When we adopted our newborn daughter, we had just moved to a new city and barely knew anyone who could babysit. On top of that, babysitters for our daughter (because she was technically a foster baby for a few months) had to be agency approved, with a background check and fingerprinting, making them pretty scarce. When we were finally able to leave her with her grandparents, there were definitely things I wasn't prepared for when I left my baby for the first time. From forgetting where she was and panicking that she wasn't by my side, to feeling guilty for missing her and guilty for not missing her, there were more than a few feels involved.
When our daughter was a few months old, we left her with my parents while we were visiting for the holidays. They live in a tiny town in central Maine and we had decided we'd go out to dinner. The closest restaurant was 10 miles away, meaning we'd have to drive there and this lightweight new mama wouldn't be having more than a drink. It wasn't 90 minutes before we were wondering what else we could do to stay out longer, as there were no late night coffee shops in rural Maine, or even a bar worth going to after the fastest fast-casual dinner ever.
So we rolled back into my parents' house after barely being gone two hours, but it turned out to be the best trial run for leaving her that we could have done. Not too long that our babysitters (who hadn't been in charge of a newborn in 25 years) got overwhelmed, and not too long that I started to really worry about her. In fact, it was just long enough to get the hang of normal conversation again, and really enjoy my husband's company.