What type of machining and materials are you looking to machine? Production/CNC level or One off Hobby manually turned stuff? Steel, Aluminum, Brass?
I have a cool mist, but I rarely use it. Most of my stuff is one off and manually turned. Mix of materials. I manually apply cutting fluids as I go.
My Jet 1024 lathe is bigger than a mini lathe but it's not huge. So I don't typically take honking cuts, where I generate a lot of heat and might benefit from coolant. For the limited occasions I do, I'll pull out the cool mist. It's been a couple of years since I last used my cool mist. So I can't really speak to lingering smell..... My shop is part of my garage, so when I have used it, I've left the garage door open.