A bit of background, I had a cat for more than 10 years, she was a very affectionate cat and loved to cuddle, but also was entirely ok on her own for some hours. That was more than 10 years ago and I consider getting a cat again. The first rescue I checked asked me whether the cat would be alone at home for 4 hours or more at any point at all...apparently this is one of their vetting criterias before they consider me to adapt any of their cats.
I wouldn't leave my cat on her own over night and I wouldn't adopt a cat if I was regularly out all day (I'm not, I WFH full time), but I probably wouldn't have thought twice about going out for an afternoon and leaving my cat at home for a few hours.
I'm happy to be told that I am wrong, it's been some time since I had a cat so I rather do some research and see what is considered the best thing to do now before getting a cat again. I wouldn't get one if I can't give it a good life.
How many hours on its own - occasionally, not regularly - would you consider ok for a cat?