In a few decades when the reward gets too small, the transaction fee will become the main compensation for nodes (miners).

~ Satoshi Nakamoto
Bitcointalk.org, 2010-02-14

Miners will always be needed to verify transactions, thereby keeping the network updated and secure.

While one needs to be aware that there are costs involved, and profitability is negligible for home miners, it is a powerful way to help secure and keep the network decentralized.

Miners last quite a few years. There are currently many Antminer S9’s for example, that have been running for over 6 years.

When miners are retired they can easily be taken apart and recycled.

Tons of fascinating innovation is happening, with people using the excess heat from miners to heat their homes, saunas, greenhouses, hot tubs, dry jerky and vegetables, heat decks, dry wood and more!