I keep a well stocked pantry in my basement which includes canned goods, paper goods, cleaning supplies and other non-perishables. By storing them in the basement, these items are in a cool, controlled environment.
As for how far in advance to store items, I buy canned goods on sale and have been able to successfully store them for years. For plastic-bottled goods it is always best to check the expiration dates.
Baked goods, such as cookies, crackers and cereals do not tend to store for very long. They become stale after a short while. Check the dates on these also.
Paper goods, such as toilet paper, towels, plates, cups, of course, can store indefinitely, but it is space that determines how much of these items to store ahead.
My parents grew up as children in the Great Depression and taught me to plan ahead. With today's gas and food prices, many people are turning to this philosophy.