How often does the "E" strong snap....

TWANG!!!! In a split second, my vigorous violin practise session ended. There was a 5 second silence....before I realised what had happen. Damm  strong snapped. A first time ever for me. And the string was changed after my exam last year which was in August, making it barely 5 months old. Overuse I hear you say? Nonsense. Oh dear, oh dear....