My experience has been that they last for more years than I tend to notice which ones are which. I’m not mad at all about their longevity.
I had 2 LED bulbs that I know for sure that I bought prior to 2015 that only recently failed. Those bulbs lasted at least 9-10 years. The rest of my bulbs I haven’t kept up with but those 2 older ones looked very distinctive with aluminum heatsink material for their bottom halves.
You can also just leave the cap intact, and and just tie the end of the cord in a knot to keep the strings together. Just loop it around itself and poke the end through the loop and tighten it to make the knot sit near the end of the cord.