If you're unfamiliar with scotchgard, it's a thin layer of protectant we apply to carpet, rugs an upholstery to ward off against stains. Pay attention to the use of the word "thin" because it can protect you against most incidents, but don't try to test its durability with a bottle of Robert Mondavi.
Whether you have a family with kids and pets or if you're a messy single guy like me who constantly spills his beer after a long day at work, scotchgard may not be a bad idea to invest in.
You never want to use too much, though. Not for safety reasons, everything we use is non-toxic and safe to be around, but mainly for comfort. If a large amount of scotchgard is applied, you'll be able to feel it and that may become uncomfortable. Just enough is just enough.
Scotchgard should be reapplied every 9-12 months, depending on how much use the treated area gets. Whatever it is that you're having scotchgard applied to, we recommend a deep cleaning first. There's really no point in adding protectant to a dirty rug or piece of furniture.