Hmm, LEDs. Volatile. Beware which LEDs you buy, and from who.
They can be superb. I've been using them throughout the house since 2011 for a massive saving in electricity, with a step reduction in the bill!
I'm also always on the look out for a better LED and trying samples as they appear on the market. Expect to aim for a genuine 100 lumen per Watt, any less from a cheap lamp is a false economy.
They can be switched as many times as you like (unlike a CFL fluorescent), but don't put high frequencies through them (eg chopper dimmer, or a bad connection) since many (the cheapest) use a simple dropper capacitor as the current source.
If they run hot the life is short, sometimes only lasting for days. Big heat-sinks help a lot, but can be ugly.
Ergo, use lots of low power LEDs for thoughtfully (tastefully?) distributed lighting on several switches, even different colour temperature zones. eg the big bay window at the end of our kitchen has 6000K GX53 to match the daylight but the rest of the kitchen is 3000K.
Forget two-wire series dimmers (L-in, L-out) they are a waste of space, but three wire dimmers (L-in, L-out, NN) and motion-detector switches (with a relay) are OK. Some rewiring needed in most houses for this. I did quite a lot.
Recently after about nine to ten years the initial 12-off batch of 3W GX53 LEDs arranged as 4 on each switch in the kitchen were down to about 50% brightness, and dimming quite noticeably in the final few months. I estimated they had done close to 40,000 hours, but the 12 off 4W GX53 of a different make from a year later in the living room are closer to 25,000hours and are being replaced in the next few days.
Unfortunately I've needed to replace with 5W GX53 because of a lack of good quality 3W. Manufacturers seem to think "Bigger number is better" NO! I need the right light not too bright a light.
The topic is actually a minefield with so many of them claiming long life but ignoring the fact they are running at way over the maximum mounting temperature recommended by the chip manufacturer for their quoted life.
When I was doing this for work, the claim was a 55C mounting surface typically offered 30,000 hours to half brightness. However too many bulb run at about 80C (hottest point measured with an optical thermometer) and often only last a few months, maybe 300 hours instead of 30,000. Chip manufacture has improved a lot since then, but the preferred operating temp is not a lot higher.
Forget guarantees unless you can find a supplier that's been doing it for several years. Often it is one container load brought in cheap, dumped on the market through Az or Eb and seller vanished after a few months with no come-back.