On every car I've ever bought, I've also paid for the extended (100k miles) warranty. On all my leases, I don't go past the factory 50k miles. I've never regretted doing this when I buy/lease.
2013 F30 335i | Sportline | Imperial Blue Metallic | Black Dakota | 6-speed | HK | Cold | Premium | 19" Staggered Sports | M-Performance Exhaust
2009 E90 335i
2007 E90 328xi