I have an old 1HP Delta Bag DC that used to take care of my whole shop. I would move it from machine to machine (I am amazed that I used to have the room to do that). It is now dedicated to my jointer.
I improved the performance by adding an American Fabric Filter bag and converting the lower bag to a solid one. I just stuffed a lawn bag into the cloth lower bag and it’s lasted a decade.
I was well aware that the filter bag was due for cleaning. The give-away on baggers is that the bags blow up like balloons. I know that the original bags that come with baggers do this somewhat from day one but, that is because they are a fraction of the size they should be. If your bags are taught, they are impeding airflow. They should be semi-soft to the inquiring finger but, I digress . . . . Here's a calculator for surface area to airflow.
I had avoided cleaning the bag because I just knew it was going to be a monstrous undertaking. In fact the whole process only took about 40 minutes and was pretty easy. The bag used to be so inflated that I could nearly get a “boing” out of it if I smacked it. It now looks like this with the motor running:
I removed the bag and used some spring clips to hold the opening shut. I shook it from top to bottom, removed the clips and dumped the spoil into the trash. I then turned the bag inside out and vacuumed it with a brush attachment. I turned it right side out, vacuumed again and re-installed the bag. The amount of airflow is dramatically increased. It seems that this little DC has nine lives and is now on number three .