#1 Tool kits
Since a lot of us have seen our parents keep some of the tools under the sink or even the whole tool kit there for easy access, we also tend to repeat that same mistake. Unfortunately, it is not the best place to keep them. Sure, it may seem efficient, especially since it would be easier to get than, say, the garage, but you are actually slowly damaging your tools by keeping them under the sink.
It may not seem like it, but the area under your sink can tend to be quite damp from time to time, especially if we are talking about the bathroom sink. You don’t need a leak to have dampness from time to time, especially if you have metal pipes: condensation can cause dampness, which can lead to corrosion and rusting on your tools! You will not see this immediately, as it will happen slowly, so do not risk it.
Keep your tools in a dry place, like a cupboard, to make sure they do not get moist and start rusting!