There is no such limit of Dowry Cases under Section 498A of the Indian Penal Code. Rest depends on the Evidence and Prosecution.
As per Section 468 CrPC, a complaint alleging commission of an offence under Section 498-A can be filed within 3 years of the alleged incident. However, Section 473 CrPC enables the Court to take cognizance of an offence after the period of limitation if it is satisfied that it is necessary so to do in the interest of justice.
The essence of the offence in Section 498-A is cruelty. It is a continuing offence and on each occasion on which the woman was subjected to cruelty, she would have a new starting point of limitation( Arun Vyas v. Anita Vyas, (1999))
I hope this solves your query.