Our Front loader (FL) has a tub clean cycle we try to run regularly. This just requires water and if we miss doing it for too long the amount of foam during the wash can be quite spectacular. Most FL these days have a tub clean cycle and it is worth using every couple of weeks if a heavy washing family, if less use then every month or so is probably ok. This cycle fills the tub with more water than normal and ensures that a lot of powder, and lint build up that can stick to the drum and tub walls is removed.
Some of the stuff suggested in the article seemed about buying something but they did offer the vinegar one (don’t bother with the bicarb or as they call it baking soda) and this will react with the alkaline washing salts left behind and help remove them. The door open stuff on a FL whether it has a magnet to do it or not is sensible. You don’t need to buy something though just leave the door ajar.
If someone is worried about a dirty seal just wipe it over with a moist microfibre or similar cloth to remove the dirt. I don’t know that I would go scrubbing it with a brush though as that may be too abrasive and help to wear the seal out sooner than needful.
If you can access the pump cover (usually behind a flap near the bottom of the front section and also nearby is typically the emergency drain hose) the occasional opening it up and checking for small objects eg coins, paperclips is not a bad idea (there will be water so lay an old towel or rags down to avoid water on the floor).
