Published at Saturday, 18 November 2017 by juan in Furniture Office, with total 39 photographs.
For starters, there is the backrest height. You want to try to find one that will allow the user of the chair to provide maximum support to the lower portion of the back. The height will vary from person to person so that backrest itself must be adjustable.
When purchasing an office chair, the first thing you want to get, if possible, is a trial period. Many distributors will allow a week. That way if there are any problems or if the chair is uncomfortable after long periods of sitting you can return it. You can't possibly know if a chair is going to be comfortable after just a few minutes of sitting.
As for armrests, they should not interfere with the work that needs to be done but should be comfortable and provide support for the arms. In general if wide movement is needed armrests should be avoided.