As a designer, how do you make choices?

I have been using  NeoPixel Mini 3535 RGB LEDs as my go to indicator on my boards.  At < $0.20 in quantity of 100, it is cheap enough, and the RGB capability gives me a bit more flexibility. 

Cool method. How many lines of code does it take to make it indicate something?

All decisions are based upon the project requirements.

If your requirement fits an old circuit, then you can reuse it.

I generally use a FET (to protect the MCU) and resistor because that is what I stock for this function.

Coding in 'C' it takes about 18 lines of code to send the serial string to the NeoPixel, which I do with a bit-banged IO port (pin).  There is an additional overhead to build the string, which is 3 lines of code for each color intensity change.  The programming string is 24 bits, for the 3 LED intensities, GRB ordering, 8 bits each. The timing is pretty critical, so the code must run with interrupts off (or at least make sure that the code can run without being interrupted).  A 'zero' is .2 to .4 us high time, while a 'one' is .58 to 1.0 us.

Doing this with bit-banged IO, there are some changes to the code that need to be made to account for the microprocessor clock speed.  As the clock speed increases, you need to add additional 'NOP' commands to keep the clocking rates correct.

Sure, it is easier to just toggle a pin, but using smaller microprocessors, pin are at a premium.  Being able to 'blink' in different colors is a nice added feature.  Also, the NeoPixels are daisy chainable, so multiple LEDs can be driven off the same pin.

I have a client that wanted 256 level programmable RGB LEDs for his project and theses are cheaper that other approaches.

And of course after you have done the code once, you can reuse it on any project without re-inventing it ...

My first response to the question was "poorly".  I always find a way that I would have preferred to use AFTER I commit to a course of action.  Then I read a bit more. 

That is so true.  I have used this same code (with timing modification) is several products/projects.  I really try to re-use code wherever possible.

Arduino IDE serial port for me usually…

<rant> but at work (industrial equipment), and on the higher level (servo drive controllers, HMIs, pid heat controllers, etc) our electrical team always goes for bleeding edge whiz-bang modules that you need a laptop and networking degree to do basic troubleshooting. As opposed to traditional PLCs and whatnot, drives me crazy. Our older equipment will last for decades because “Johnny from maintenance” can easily diagnose with a basic multimeter. Newer equipment becomes scrap when a smartmotor starts to flake out and they can’t trouble shoot it, and can’t replace it because they don’t have the software to program it or a copy of the program itself. </end rant>

So your detailed question doesn't really match the headline. Speaking to that, I generally choose to explore something I haven't done before, if it is an important part of what I'm trying to do. If it isn't I generally reuse something I've already done or go online to see how someone else did it.

In the instant case you're asking about, it's not something important to the product/project, just a debug tool, so I do the simplest thing: LED and a resistor. When I need something more useful than a few bits, I build a virtual front panel.