1.1.7 Comfortable and safe for one, but not for all?
There may be many users of a single computer in your house, and each person is a different shape and size. This means that a single layout of the work area may not meet the needs of all of the users. If you have an adjustable chair or desk, it is sensible for each user to adjust it to fit them when they come to use the computer. You may find it helpful to mark the chair or desk to show the most comfortable settings for each person.
You may need to place the monitor on top of something to raise it to the right height for different people. If the height needs to be changed frequently you might want to consider using an adjustable monitor arm that will allow you to move the monitor easily (and so help avoid the possibility of back injury).
A footrest of some form may be needed if users are not very tall. Such equipment does not have to be purpose built (though well designed equipment may be superior in some respects).
Beware of products claiming to be 'ergonomic'. While some may be very effective, things can only be ergonomic if they are used in the correct way for given people and given circumstances. Remember, things are ergonomic only if they are safe, comfortable and easy for the person using them. Things should be designed or set up so that they suit the user and NOT so the user has to fit themselves to the technology.