Bare minimum (legal minimum) is:
red rear reflector, center mounted on the bike.
white or amber reflectors on the wheels...may be removed if your tires have a reflective sidewall.
white or amber reflectors on pedals, front and back. This one is mostly unenforced...plus how often does anyone see the reflector on a pedal.
Front light visible by drivers no less than 300ft. Note they said light NOT reflector...actually front reflectors are not sked for in most jurisdictions...so I just remove mine.
now..to be lighted reasonably...
Add in a red rear light...preferably flashing and having at 300ft visibility at the least.
consider refletivetape on strategic parts of your bike.
Also mount a red flash
er to the back o your helmet. i have a tiny flashing reflector i zip-tied to mine.
the key is making sure your visible from a distance. It's better to overdo it in this case as far as how much lighting. For example...come this weekend...i'm buying a second headlight...