Comment 5 for bug 1373862

Right, 80% may not make a lot of sense actually, depending on the scenario. Unfortunately, it is an established default, and I think we would need to proceed carefully.

I'm all for sensible defaults. I do think we need to take a hard look at the potential impact of a default charm config option value change, any time that is considered. My main concern is that, in changing a default value, we risk breaking existing users. As long as we give advanced notice, eta, updated docs, release notes, etc., I think it should be a completely reasonable thing to pursue a default value change.

We would also need to take a look at the bundles in the charm store to identify and adjust any which rely on the established default value. For example... ;-) and I'm not at all biased:
https://jujucharms.com/openstack-base/36 (https://api.jujucharms.com/charmstore/v4/bundle/openstack-base-36/archive/bundle.yaml)

That one is easy enough to identify and fix. We just need to take the time to evaluate, discuss, identify the risks and the things-to-do, then do them, if that is the consensus.