If over 100k+ miles and have all original parts, inspect and replace as many small suspension parts as you can. Parts such as sway bar bushings, control arm bushings, ball joints, tie rod ends (inner and outer), and definitely end links. You have to disconnect end links, so you might as well put new ones in.
^ this
Unless you have relatively low miles on your car, chances are some of your other suspension components will need replacing after you lower it. The more you lower your car, the more stress you put on all the other parts of your suspension.
Most of what he listed are relatively cheap to replace. If you decide to get BC coils, they do come with new end links. I'm not sure what other brand of coils come with them as well.
While its recommended that you give the entire suspension a look-over when you lower your car, technically the only thing you NEED is either new springs + struts or a complete coilover system. When I first dropped my Celica on BCs, I maxxed it out and didn't replace any other parts. I didn't even have a rear camber kit. I was sitting pretty low, but luckily none of my other suspension parts ever went bad.
To put it into context of the age of the car, however, my Celica had maybe 70 or 75K on it when I first lowered it in 2012, which is relatively low for a model year 2000 car. In contrast, I owned a 2005 RSX-S which I lowered at 120K. About a month after lowering it I had ripped the CV boots and my bushings were completely shot. Your mileage may vary and you may or may not have parts failing on you after you lower your car, but to be on the safe side you should at least consider replacing the other parts of your suspension as well.
And for the love of god, even if you don't decide to replace any other parts, at least get a proper alignment soon after you lower it. That alone will make a world of difference.
