“Is it bad to crack your back every day?”

yes you need stability in your back

It is not bad to "crack" your back every day. Popping the joints repeatedly (multiple times in a day) can lead to loose ligaments that surround the joint. The bigger question should be why you feel the need to "crack" it everyday? Often, if there is misalignment that is not corrected, you will feel the need to "crack" the joint frequently to get some short-term relief. If you get an exam by a good chiropractic physician and determine the cause of stress, the doctor should be able to provide a series of treatments to correct the problem.

There is no evidence that daily popping of any joint will cause arthritis. Most people who do that or who have enjoyed chiropractic adjustments know that they get a wonderful feeling from the joint being popped. That is because popping a joint (called joint cavitation) causes a release of pain relieving and mood enhancing chemicals that positively affect the nervous system. The more important question is why one feels a need to crack one's back every day. Except for those who are being treated for an acute neck or back injury, no one gets daily chiropractic adjustments. Furthermore, those daily adjustments for acute injuries will only be given for up to two or three weeks. If one is popping his neck or back daily, it means that there is an underlying spinal issue that is not being fixed. That person is basically giving himself a manipulation aspirin that covers the symptoms and does not actually fix the problem. 
A problem at one spinal level will cause the joints of the spine around that problem to shift to compensate for the vertebra that is malfunctioning. Popping one's own back will often pop those compensations without actually moving the joint that is causing the problem. That might be why that person would feel a need to do it every day. It would be better to get a chiropractor to examine the spine, determine where the real problem is, and to initiate a treatment regimen that will actually fix the problem. While chronic daily spine popping may feel good, it is my experience that it can lead to over stretched ligaments. That can cause joint instability and it makes it more difficult to fix the problem once one begins chiropractic care.

Cheers,

Dr. Neill H. Payne

It can be because if you have to continue to crack it daily there may be some kind of malfunction of the back that needs attention before it becomes a real problem.

This is usually a perfectly safe thing to do. If you have pain at the area where you are cracking your back, then I recommend seeking a professional examination from a Chiropractor.