Military equipment has a circumstantial life cycle. It can usually be extended by modernization, but this time depends on the susceptibility to modernization of a given structure. In addition, it must be remembered that the life cycle cannot be extended indefinitely. Nevertheless, as it turns out, frequently a given kind of equipment can gain a second life in the course of reconstruction and change of the function it is expected to play. Referring to 1 of the erstwhile materials on the T-72 and PT-91 main conflict tanks operated by the Polish Army, it is worth mentioning the subject of converting specified machines into armored personnel carriers and specialized combat vehicles.