Owning your own punchbag gives you a workout friend who will always be there if your willing to be there too. It is a great stress relief if you have had a pent up day, and a positive outlet that you can unleash some fury on. You don't even have to be a top fighter skill wise in order to use it. For those who train Martial Arts it is a deeper matter, for we can do more than just hit and snarl. The bag can be used to wrestle with if its heavy, provided you have safely wrapped up any chains that could whip you in the mush! I like to put a jacket on it and pull it about "PUNK"
A good workout is to do your kicks and punches and then when your stand up is done, unhook the bag and then wrestle with it on the ground. The bag is dead...lifeless so its up to you to visualise and pretend its an attacker on or below you. Get used to been on the floor so if you end up there it wont scare you as much.
Move around when standing, train all ranges and try it without gloves to prepare you for combat. It will get you fit in no time and the heavier the more strength benefit you will receive. Try hitting nonstop for one minute, try talking to the bag (not the wall) Some lighter bags can be used to squat or curl with, some Kung Fu students with stand in a horse stance resting the bag on their forearms. One big mistake is trying to look good, just hit the dam thing. We all can look fast and powerful on the bag so just remember it is just one tool with many uses, but the quality of the workout will depend on your own ability to think alone.