AL NZ, that about sums up the typical experience most people have with chaincases. they're great at keeping your drivetrain and your pants clean, but they do make the simplest repairs (even repairing a flat!) a major pain! i upgraded the rear cog on my '51 raleigh from an 18T to a 22T, and i just bought a cheap new chain to deal with the extra 4 links. it is nice that the chaincases are designed to accommodate a 22T cog. if you ever lose the chain inside the chaincase, just hang the bike from the front wheel-- the chain dangles down.

here's my chaincase, hiding the 22T cog: