Electronic BP machines can often give inaccurate readings, but not by much. I have both; a machine and a cuff.
I would think you should be able to monitor your BP readings at home. Do you have high BP? Did you doctor tell you to take it at home?
Best thing to do is take your machine with you to the next Dr appointment.
Have them check you blood pressure then check it on the machine...
I have two machines now, just got a new one.
I used them both and they were only a few numbers apart from each other but the pulse was right on.
I like OMRON brand myself, don't go cheap....