No, only LED bulbs that are suitable for it.
There are LED bulbs that dim with phase cut and there are those with phase cut. Also, the minimum wattage of the dimmer is important for the LED bulb to dim properly? An LED dimmer of min 1w is best. Most old dimmers work on e.g. 20w. This means you need min 4 lamps of 5w to dim the LED properly without flickering.
Yes this is perfectly possible. A dimmable LED does not need a dimmer to work. A non-dimmable led will e.g. not work well with a dimmer.
This is usually due to a loss on your switch. You can solve this with e.g. an antiflicker module. Or a changeover switch.
There are several factors that can cause an LED bulb to fail quickly.
- Heat: An LED fails quickly if it cannot cool properly.
- Net pollution: One of the biggest causes of rapid failure is mains contamination from e.g. fluorescent ballasts, energy-saving bulbs, fridges ect....