Can anything bad happen if I dont fix this dead tooth? I've had it for so long already

I have a discolored, dead tooth...I had this since I was a kid. I am now 46 years old. My dentist is suggesting root canal and using a crown to fix this. I don't have any pain in the area and no negative affects from this other than the fact that it does not look very nice. I was just wondering if anything bad can occur if I just leave this untreated? Dont forget that I have had it for so long already with no bad affects up to now. Thanks in advance.