Assalaam Alaikum,
If a person had stop praying for a considerable amount of time is he out of the fold of Islam. Only Allah swt can guide he comes back after years an starts to make tauba and starts back praying his daily prayer but before that he live a life of sin and disobedience to Allah swt would accept his tauba and prayers .Would he have to say the shahadah again. Even if he had says he still believes is the truth.
Wa Alaikum Assalaam,
If a person had stop praying for a considerable amount of time, but still considered himself to be a Muslim, then he is not out of the fold of Islam. He will still continue to be a Muslim, but will be guilty of a major sin. If he turns in sincere repentance to Allah, and earnestly begs for His forgiveness and begins to perform his daily prayers (Salah), then it is hoped that Allah will forgive him and accept his tauba and prayers. It is however, essential upon him to make up for all the Salah he missed in the past, and must make a firm resolve that he will not return to the sins which he committed in the past.
If he knew very well that he never gave up Islam and always had Iman (Faith) as a Muslim, then it will not be essential for him to say the Shahadah again. If he is doubtful on account of the sinful life he lived in the past, then he should say it again so that he can re-affirm his faith and submission to Allah.
And Allah Knows Best.
Mufti Waseem Khan.
9/5/17.