I used to eat out about 80% of the time, at huge expense, but since buying a pressure cooker its 5%...
There are plenty of recipes where you just throw in the ingredients, add a specific amount of water, set a specific time, and come back in 20minutes to a perfectly cooked meal. Its far less hassle than cooking with a pan etc, and uses less energy and water.
Smaller items like hard-boiled eggs take about 5 minutes in total.
You're also not venting cooking fumes and steam (and combusted natural gas) into your kitchen, so air quality, mold etc. is much improved.