The problem is that to monitor your sleeping patterns, a valuable feature most of these new smartwatches support, the watch needs to be on your wrist. So leaving your watch charging overnight while you slumber isn’t going to work. But smartwatches have small batteries compared to smartphones, so should only take 2 - 4 hours to fully charge, depending on the model.
The first digital watch, which debuted in 1972, was the Pulsar manufactured by Hamilton Watch Company. "Pulsar" became a brand name which would later be acquired by Seiko in 1978. In 1982, a Pulsar watch (NL C01) was released which could store 24 digits, making it most likely the first watch with user-programmable memory, or "memorybank" watch.[9] With the introduction of personal computers in the 1980s, Seiko began to develop computers in the form of watches. The Data 2000 watch (1983) came with an external keyboard for data-entry. Data was synced from the keyboard to the watch via electro-magnetic coupling (wireless docking). The name comes from its ability to store 2000 characters. The D409 was the first Seiko model with on-board data entry (via a miniature keyboard) and featured a dot matrix display.[10] Its memory was tiny, at only 112 digits.[9] It was released in 1984, in gold, silver and black.[11] These models were followed by many others by Seiko during the 1980s, most notably the "RC Series": During the 1980s, Casio began to market a successful line of "computer watches", in addition to its calculator watches. Most notable was the Casio data bank series. Novelty "game watches", such as the Nelsonic game watches, were also produced by Casio and other companies.[citation needed]

Fitbit Versa: The Fitbit is the health tracker for the masses and they have a model for every need. But the best option for adults who do a moderate amount of exercise and just want to keep tabs on their general fitness (ie: most of us), the Fitbit Versa is a great choice. It's an entry-level smartwatch. For more on the Fitbit Versa’s various attributes, read my in-depth review. ($350)
Samsung's Galaxy Watch, a Tizen OS watch (starting at $329), is our favorite smartwatch for Android users. In addition to up to four days of battery life and a great design, the Galaxy Watch offers built-in GPS, heart rate sensor, water-resistance, Samsung Pay support, plus a nifty rotating bezel for navigating the interface. You can also download music from Spotify to the watch for offline listening. However, you get far fewer apps than you would with a Wear OS watch.