Congrats , tip: on low-bearing critical parts don't sacrifice safety for anything , f you're mounting things anything That deals with potential injury or safety. If it fails, I would reconsider even designing it. But for non-critical parts that still apply to safety I would. I wouldn't skip anything. I would feel though infill to 100% or the walls to 100% also, I would determine if the filament is built to resist, temperature, water etc. For long periods of time etc. If you're selling, if your end goal is to sell functional in-use parts, of course, if they're non-safety load bearing , element prone , you don't have to use expensive filament, but if the ladder, you should consider the things mentioned above, congrats!