the way which cable is connected to the head is to 2 points, tip and sleeve on the head itself.
The only thing that link the cable and these 2 points is the soldering lead. The strength of the solder is usually quite strong. But constant tugging and pressure when pulling out the cable via the cable itself instead of the head, is going to add extra pressure on the 2 points over time. Thus if possible, always pull out the cable via the head itself instead of tugging the cable.
If thats quite hard, as in your case, another way to minimise the pull, is on the guitar output jack itself. Within the guitar output jack, theres also 2 point which will get in contact with the instrument cable when the cable is inserted. These 2 points on the geetar output jack, can be adjusted so that it wont get too tight when the cable is inserted or removal. Thus when removing cable, even if having to pull out the cable, it wont be so tight, indirectly lessen the pressure on the cable head/plug.
if you are not comfortable with opening up the output jack on the geetar to adjust the points, you can ask any geetar tech to do it. But do take not that you might have to pay, even if its just a really simple thing to do.
If you are comfortable opening thigns up and explore, just do it. You will learn a thing or 2, even if something goes wrong.
