My shop is in a one car garage in the basement of a hillside house. My lathe and corresponding tools are in the back corner of the garage. There is no ventilation except when the big door is open in nice weather. The corner is where my well pipes come in and I also have the water softener. In other words, lot of pipes. In summer there is some sweating of the pipes and moisture. I have never had a big problem with rust. Most of my lathe tools are just fine. But, yesterday I found the Marples brand tools were quite rusty. Others are OK. Must be a different steel. BTW: "others" includes some antique 'cast steel' some old Craftsman and newer name brands.
This Marple skew is going to take some work to get clean again. As a precaution I'm going to put Johnson paste wax on all tools as I do the beds of my large tools.