While you wait at the nauseatingly retro laundromat, praying for your clothing to be fully dried so you can get home before 1:00 am, I hope I can enlighten you as to the convenience of these coin-operated communal cleaning devices. Clean clothing was a lot more inconvenient in the past which is why many people went without. A woman of wealth had many fine articles of clothing and a man of taste requires at least seven clean shirts a week. That is unless you were Charles James Fox, in which case you were lucky if he even made it outside his house in something other than his nightshirt. But for those who enjoy good hygiene, an essential article of your household would have to be a laundress or a washerwoman in the least.
Linen was to the 18th century as cotton is today. Not only was it what men's shirts were made with but also many undergarments and linens. Cleaning the pure white material was not as simple as throwing it in the wash on a warm/cold setting. Linen particularly had to be boiled in vats. Clothing also couldn't be considered clean until you had scrubbed it until your knuckles were raw. Soap, bleach, lye, and starch were used in the laundering process. The various materials also had to be dried and ironed. Some garments had to literally taken apart and sewn together again to prevent damage in the washing process. The whole process was back-breaking and extremely time consuming. If normal household servants took on the laundry for the whole house, you could depend on none of the regular tasks of the day being completed.
Due to the overall hassle of "doing the laundry" washerwomen were quite the essential. Just as our contemporary colleges provide launderettes for students to learn firsthand about mixing colors and whites, men going to university in the 18th century were provided with a laundress to keep their bed linens and clothing clean and mended. Of course this meant any young laundresses with easy access to bachelors' dorms were common victims to upper class charms and would find themselves doing more than laundering.
But beside resisting the charms of dashing young students, being a laundress or washerwoman wasn't the worst way for a woman to make a living. There was always a steady stream of work, and although it was difficult and time consuming it would feed you and your children. Washing and mending clothing for a living was one of the top occupations for women for around 600 years. Of course those statistics exclude the most ancient of female professions, but that was for those who couldn't take the (steaming) heat!