5S and TPM are two good tools that we (at my company) we have been using for the last about 10 years to keep our machines and equipements maintained.
But what I would like to share here with you is the tremendous job the maintenance team has been doing at our plant in the city of Hoshiarpur. The plant was established way back in 1973. The plant machinary has been maintained so well that it continues to run even today. As a matter of fact the production levels are comparable with the latest modern high tech machines and so is the quality being generated (crucial worn out parts are changed as and when required).
The plant has been running for nearly 40 years, the machines have over run their depriciation period and are virtually free. It is not that the team is spending heavy money on spares and maintenance, but they have been following a very strict maintenance schedule. In addition to this the team has the habit of preventing a problem from repeating.
What I am trying to drive here is that if taken care of the assets of a plant can last for a very long time, but then there has to be dedication and sincerity.