  In this study we model the warranty claims process and evaluate the warranty
servicing costs under non-renewing and renewing free repair warranties. We
assume that the repair time for rectifying the claims is non-zero and the
repair cost is a function of the length of the repair time. To accommodate the
ageing of the product and repair equipment, we use a decreasing geometric
process to model the consecutive operational times and an increasing geometric
process to model the consecutive repair times. We identify and study the
alternating geometric process (AGP), which is an alternating process with
cycles consisting of the item's operational time followed by the corresponding
repair time. We derive new results for the AGP in finite horizon and use them
to evaluate the warranty costs over the warranty period and over the life cycle
of the product under a non-renewing free repair warranty (NRFRW), a renewing
free repair warranty (RFRW) and a restricted renewing free repair warranty
(RRFRW(n)). Properties of the model are demonstrated using a simulation study.
