I just mist mine daily and it is happy. It depends on where you live and how dry the air is.
The first thing you should do is shower it off c TEPID water to rinse away any product used on the plant to make it "perfect" for the service. This will unclog the stomata (pores on the undersides of leaves) and generally freshen the plant up a bit. I also put mine out rainy days, as long as it is a warm rain.

I'm sorry for your loss.

Humidity trays don't actually raise humidity for plants enough for them to be even worth the simple effort. To really affect the humidity in a space, you have to use a room humidifier.

That being said, if you have a bathroom with a window, you could put the Peace Lily in there and they would love it because they would get humidity there. It doesn't even have to be right near the window.

Z

Thanks for the advice. I will get it showered as soon as I can and try misting.

The bathroom's too small for this huge plant, so it's in the living room. We do have a whole house humidifier that runs with the furnace in the winter, so hopefully that will help too.