It almost seems like someone from BBC has posted about this before, but I can't remember who or when or how thoroughly, so I shall share my thoughts. Quite regularly, I hear someone at our church or in the larger Christian community say something like the following. "If just 1 soul gets saved then (such and such) will all be worth it."
I don't think I ever liked this mentality, but I especially don't like it nowadays. My problem with it is twofold. First, it seems to ignore 'stewardship.' If you take this mentality to its logical conclusion, a church would be doing good to spend its entire budget to reach 1 person. That's poor stewardship of time, effort & resources. Secondly, such a mentality is usually attached to very non-relational ministries like tract throwing or sign holding (at least in my observance). It seems to me we can set our goals a bit higher than 1 and use our time, talent, and treasure a bit more wisely than all that.