The service life of the high quality stainless steel  towel warmers almost unlimited.  They are more resistant to mechanical damage than the equivalents of copper or brass,  they do not have a special coating that can peel off under the influence of wet conditions.  They just polished to a mirror finish.  That is why they retain their appearance over the entire lifetime.  In case, if during the operation minor scratches will appear  or glitter fades, you can restore the appearance with polishing paste and a soft sponge.

The only problem you may encounter is electrocorrosion. Stainless steel does not normally sensitive to oxygen, but the interaction of oxygen with stray current leads to electrocorrosion.  The appearance of stray currents in the hot water heating system occur for various reasons.

This may be caused by the fact that some users are grounded their electric appliance through stand tube, using of magnetic filters for water softening, water chemistry is also very important factor.

Under normal conditions, is difficult to determine the presence of stray currents, but the problem is usually solved by the usual ground, which divert currents and protects your system against electrocorrosion. For stainless steel towel warmers  connection to ground  is a mandatory requirement, to avoid electrocorrosion.