Hello and welcome, Chas!
JimmyBob and Boombox have said what I would have said about the humidity issue. Planet Waves stuff is good value and works well.
One or two other protective steps to take are:
Send small children and pets to boarding school or kennels - but if you can't do this, leave the guitar in the case when you are not playing it, or consider a decent stand if you want to gaze at your lovely Avalon. Leaning the guitar against sofas, tables etc, is asking for trouble. I use Hercules stands - but there are lots of cheaper ones that will do a job.
Don't leave the guitar in a closed car in hot weather, or take it sunbathing, or leave it out in the rain.
Don't use string sets heavier than 0.13 gauge. Stick to 11s, 12s or 13s, unless you are taking the tension off by using lowered tunings.
Don't lend it to Tommy Emmanuel!
http://uk.images.search.yahoo.com/image ... Hmzrnopdua
Just a few thoughts!
Long may you strum!
John