Apple warns you in one of its knowledge articles how terrible and unsafe it is to jail break. Security and instability issues.

The question you are probably asking is do they really happen, is it just a myth to scare people off. Well for a week nothing went wrong. I tried and bought a number of tweaks and themes, but then just realised having a few simple tweaks was all that is needed to make a big impact.

However, I have had the iPhone 5 suddenly go into safe mode during the night. And then my folders were slightly messed up. The iPad Mini had issues with moving apps on to a different page. After analysing the issue, it boils down to springtomise 2 tweak having a conflict somewhere. Problem is you really need this tweak. So for the time being I am going to keep the jail break as the pros seriously outshine the cons.

Just be aware you can get some odd issues with stability.

Update. Some apps aren’t working correctly with the jail break, so I am deciding whether to go back to a factory standard iPhone. Just working out the pros and cons.