Buying incandescent bulbs now to store them for when they become unavailable later is simply wasting money. An LED will use less wattage than an incandescent bulb with the same luminosity. This means less electricity and lower electric bills. Even an expensive LED will save you money over time compared to having to buy and replace several incandescent bulbs (that use more electricity). Unless, of course you're producing enough of your own electricity 'for free' with solar panels.
There's also the cost saving of not having to frequently replace hard-to-reach / industrial lighting that requires hiring workers to change them and the cost of a lift or scaffolding.
LEDs can replace incandescent and be nigh impossible to tell the difference unless you stare at the bulb. LEDs can produce warm yellowish light or bright bluish light (or both). If an LED light looks out of place, it's the fault of the person who chose the wrong LED bulb.
The LED itself should last 10 years or more (unless you're using them in a way they weren't meant to be used, e.g., using an indoor bulb outdoors, or putting an LED bulb not rated for a closed fixture in a closed fixture).
The LED itself will lose luminosity over time (over the course of 10 years or more). Get a luminosity app for your smart phone and take some measurements for a baseline. Then a decade later when "it seems dim in here," you can measure again to see if it's the bulbs, or your fading vision due to age.
What is often the problem with 'bad LEDs' is the driver (a circuit board in the base of the bulb that takes the AC and transforms it into electricity the bulb can use). And it's the cheapo brands (mostly made overseas) that have the recurring issue with the driver. Do the research to find the best reviewed and tested LED bulbs.
Flickering can have several causes. Most often, a rheostat (dimmer) made for incandescent is being used for the LED, or, the LED itself isn't made to dim. (Don't forget we all had to deal with the flickering of fluorescent tubes everywhere!).
If your electrician can't figure it out, find one who can. I dealt with an electrician during conversion of my industrial building from fluorescent bulbs (most were burned out) to LEDs. And when I asked him what kind of lumens would be needed, he asked me, "What's a lumen"? He was a disaster.
LED bulbs can flicker because there are voltage fluctuations in your wiring or the wiring is loose and needs to be repaired.
brennan-electric.com