Becoming a Muslim through marriage.
Q. If one has become muslim through marriage, but did not always stay on the path and has finally decided to follow the Deen, should she/he re-do the Shahadah?
A. If, based on one’s actions, one has done such things or uttered such statements that show that one was no longer a Muslim, then it is essential to repeat the Shahadah and even the marriage. However, if it did not reach to this extent, and it was simply a matter of laziness to practice Islam and one did not give up Islam, then it is not a requirement to re-do the Shahadah. Howbeit, it should be a common practice for all Muslims to regularly recite the Kalimah of Shahadah. This strengthens your faith and refreshens your Imaan.
And Allah knows best.
Mufti Waseem Khan