Further to the above answers, my neighbour has two,approx twenty feet from the houses, huge, I had voiced my concerns, but now the roots are appearing above ground, in his garden luckily enough, Now he's decided to have them removed.
What is little known in this country, is that in Australia, they are known as 'Widow makers', because when they reach a certain age, (I don't know what it is), they can suddenly shed the odd branch, Self pruning if you like.
They got that name, because unsuspecting families would picic under them, then suddenly a branch would decide to join the fun.