Movies and TV series set on contemporary times can be dated based on looking at different technologies used on them. Especially during the times of rapid technological progress in certain areas for example looking at the computers or phones.
For the really old movies it's harder to get down to a span of few years. The really old landlines didn't change that much for decades. The old rotary phones also stayed for decades, but at least you get a little closer. The era of phones with number pads was even shorter, but still you would only get down to a span of decade or so.
After the mobile revolution it became much easier. The phones evolved so fast there is a period when you can look at the phones and tell the exact year it was filmed.
But during the past ten years or so the evolution stopped. Sure they have still grown gradually bigger, but the overall design hasn't changed that much. It's hard to see the fine details that might set the models of different years apart besides the quite recent introduction of the foldable phones, yet they are still quite rare.
So we have come around the full circle on phone development after a rapid cycle of iteration through the early days of mobile phone form factors. It's even hard to tell the brands apart these days, even less so the manufacturing year. Need to start looking for something else to date the newer shows.