A couple of times this week I've had to commute home as night was falling or later still. I have a little light for the front which I expect to keep as a blinkie, and I have one of those new, cool Cateye put-it-anywhere red blinkies for the back (put it on the seatpost in seconds). I commute within 100% Manhattan, currently a mix of Greenway and streets. The streets are better lit, but require more visibility than the Greenway, so I don't think there's much of a difference there with respect to lighting needs.

What should I do to equip myself for the inevitably darker commutes later this year? I haven't year-round commuted on a bike since '96/'97 so I'm a bit out of the loop when it comes to more powerful lights. Plus I have "special needs" as a folding bike rider (have to be able to instantly remove any hardware so I can fold the bike!). I cruise on my folder on the flat sections of my ride between 28-32km/h (clearly speed affects choice of lighting).

Any suggestions? Note that my folder doesn't have any braze-ons for a bottle cage, but I do have a tricked-out backpack which maybe could hold a battery.

I don't know much about lights, but there are a variety of clip/bolt-on water bottle cages. Hose clamps from an auto store also work in a pinch.

Folder, big bike, what's the diff? Adequate lights and reflectors, and you're good to go!

Two Fish makes this holder which conveniently straps onto folders.

The only difference I can see with the folders and the regular bikes as far as lights or other accessories go is the ability to detach the unit when not needed is more required on the folding bikes than on regular non-folders.

The hot ticket for one who regularly commutes after dark is a hub dynamo. It requires some initial investment, as you must have your front wheel rebuilt with the new hub, but a hub dynamo is very efficient when compared to a tire-driven dynamo. There's less pedal effort required, it's quiet, and the lights don't go out when the tires get wet (tire driven dynamos tend to slip when the sidewall gets wet.) And forget about batteries and chargers etc.

There are lights specifically made for use with dynamos, with a capacitor built in, which will remain on for a time after motion has stopped, so your lights don't go out when you stop at an intersection.

The downside is that you carry the weight of the dynamo and lights with you all the time.
The benefit is that you have the dynamo and lights with you all the time.

There's a lot of info here:
https://www.peterwhitecycles.com/Schmidt-Lumotec.asp

Also, do a search for hub dynamo and you will uncover a wealth of information and opinion.