Did probability of warranty claim change over time?

I am working on a problem in which I am trying to determine if the probability of a warranty claim is changing over time. I have a list of serial numbers, when the product was produced, when it was sold, and if/when it came back for a warranty. These are all important parameters because the use of the product can change throughout the year. I am trying to come up with a good model for the system and am having trouble formulating it. I know that I want to model a binomial distribution; however, beyond that I’m unsure. I was thinking that the Gaussian random walk seemed a good paradigm?

Any help would be appreciated