The modern steels, even those of high quality, due to a bad preservation of the knife could present problems of corrosion over time, therefore we always must try to take care of our blades (clearly there are types of steels that will require greater attention than others) .
Even stainless steel if exposed to the right conditions can rust! For example, if you live in seaside areas, you should pay more attention to the maintenance of your knives (both for the salty environment and because in the coastal areas the humidity is generally higher); in this case it will be necessary to protect the blades with a film of oil before storing them.

For knives that you will use in contact with food I suggest the universal Ballistol oil, which is natural and edible (it goes well for practically everything, even for wooden handles, leather sheaths, and other materials).

For all other knives there are other products, such as WD-40 but also Ballistol specific firearms products that are excellent. Personally, having also firearms to clean, I have tried many products of the Ballistol firearms line and I suggest the Gunex spray; on the pivots and ball bearings of the folding knives instead I use the Guncer spray (which contains nanoceramic additives, non-resin, does not contain silicone or PTFE).

Here are a few tips:

• Do not store knives in their sheaths for long period (especially the leather collects moisture and creates pits on the blade)
• Keep your knife dry in its entirety , not just the blade.
• Keep your knife clean, particularly moving parts and locking device in folding knives.
• Keep your knife oiled; especially blade and pivot points on folding knives.
• Do not use the knife as a can opener, chisel, pry bar, screwdriver or for any heavy work for which it was not designed. Also, don't use the back of your knife as a hammer (especially in folding knife, it may break the springs, handles or pin).
• Keep your knife sharp. A sharp blade is safer than a dull one.

Always remember that well-maintained knives will perform better, last longer, and provide the owner years and years of satisfaction.