For bathroom drains (tub, shower, and sink) the most common stuff that clogs them is hair.
You can avoid clogged bathroom drains by pouring a little bleach (maybe half a cup) into each drain once a month, but be sure you add bleach at a time when the drain will not be used for several hours.
Below every drain is a P trap whose purpose is to hold water so the smell of the sewer gases does not enter our homes. This is where your hair accumulates until eventually the drain becomes clogged.
You pour in the bleach, it sits in the P-trap, and over the course of a few hours it dissolves the hair.
Adding a half cup of bleach to your drains every month or so should forever eliminate the need to use products such as Liquid Plumber.
For kitchen drains, which are more likely to be clogged by food stuff, you use an Enzyme drain cleaners instead.
The basic idea is the same, but the specific stuff you pour down the drain differs.
Again, I recommend a monthly “servicing” with the enzyme drain cleaner product.
If your drains ever do become clogged and you need professional help, please contact us.