In this paper, we study the viability of a peer-to-peer backup system on nowadays internet connections. In particular, we show that peer lifetime estimation can be used to reduce the maintenance cost of peer-to-peer backup. Previous studies have shown that lifetimes in a peer-to-peer system follow a Pareto distribution. Consequently, peers can be sorted on their expected lifetimes, depending only on the length of their history in the system. By carefully selecting the peers on which backup data is stored, repairing cost can be highly reduced for long-term backup users, while it is still acceptable for new users. The efficiency of this technique is evaluated through simulations of a state-of-the-art peer-to- peer backup system.