Mine is stored outdoors for eight months every year (actually for an entire year because I just go once place in the summer and stay there)and every month I exercise it. Oil is changed about a month before I leave for the summer. In other words, I DON'T change it when I come back home. Since I don't have electricity available in storage, my batteries aren't on a trickle charger. However, since I have a small solar panel for my house batteries, I do use a Battery Minder for my chassis battery.
Since my answers are obviously different than the one above me and may be different from those who follow, you will see the answers can be all over the board. It also depends on where you are, the availability of storage services, cost, etc. If you maintain your RV properly it will last that much longer. Ideally, storing it indoors and using it at least once a month would be ideal.
Denny & Kylene, Abby (Golden) and Josie (Sheltie),
2004 Itasca Suncruiser 38R, W22, Ultrapower
2012 Jeep Wrangler Sport Unlimited