With the current advancements achieved in the area of speaker verification, a significant performance is obtained under sufficient data conditions. Whereas when there comes a constraint in the amount of speech data, it reflects directly on the performance. This paper presents initial speaker verification studies under variable duration test segments over a standard canned database and, then, studies for variable duration test segments over a database collected from a practical speaker verification system. The latter case helps to explore session variability issues and its impact on speaker verification. This information is used for remodeling of the enrolled speaker models, which in turn improves the system performance significantly. © Springer India 2015.