> Now lamps have a limited lifespan because of the manufacturers, so they have more sales. No, because it is (well, was, before CFLs and LEDs for lighting) act

> Now lamps have a limited lifespan because of the manufacturers, so they have more sales. No, because it is (well, was, before CFLs and LEDs for lighting) actually more economical for the customer. At least in recent times, the largest chunk of the costs of owning and using a light bulb was the energy used over its lifetime, not the price to buy one. A typical 60 Watt ligh bulb cost 0.50 to maybe 1 dollar, the electricity to make it produce light for 1000 hours about 7 to 15 dollars. The tradeoff was simply between making it more efficient at converting electricity into light, which requires running it at higher temperatures, which reduces the lifespan, or making it last longer, at the cost of making it less efficient and thus more expensive to use.