If you are using incandescent bulbs, and you replace your most-commonly-used ones with LED bulbs, you will save enough money on electricity to pay for the new bulbs within a reasonable time.
As usual, It Depends (tm).
I bought a $10 (at the current exchange rate) LED bulb for my desk lamp, and figured it'll pay itself off in 15-16 months.
After 3 months, the bulb was dead. I was in an adjacent room when I realized the light had gone out, and went to check it out. The first thing that greeted me was the smell of burned electronics. The second thing happened when I tried to unscrew the bulb and got burned by the heat. Took about 15 minutes for the defective bulb to cool down to room temperature.
The seller didn't want to honor the warranty. I said the bulb was in a desk lamp, they said "ah, but it should have been pointing upwards" (?!). I was legally entitled to getting a replacement through EU laws (no questions asked during the first six months), but they were out of replacements, so I just said "screw it, too much time spent on this shit" and went back to incandescents.
The cat also immediately went back to sleep below a brand new $0.5 incandescent, whereas she'd been avoiding the LED (no heat).
Bottom line, I lost $10 and had I not have been home when the lamp was turned on, the house would have burned down. I'll stick to incandescents until I die, thank you very much. When they fail, nothing can ever go wrong. Saving electricity vs. charred remains of what used to be your home is a no-brainer.