I'm sorry I have to disagree...

You can look at an internal combustion engine and figure which end turns and which end doesn't. You can figure where to bolt it down and couple it up. You can figure where to plumb the volts (if any), and fuel (and what kind) and where to plumb the water. But if you want to adjust timing, set spacing and clearances or other critical functions - guess what? You READ the manufacturers DATASHEET.

But a PIC is just a plain black box with a heap of legs sticking out of it...

Until you consult the Datasheet, you don't even know which legs need volts on them or even how much...

Until you consult the Datasheet, you don't know where to plug-in your Xtal, or Resonator, or what kind will work or how to enable the internal oscillator...

Until you consult your Datasheet, you don't know where the MCLR pin is, or what to do with it or how to disable it...

Until you consult the Datasheet, you don't know what pins have bi-directional I/O and what pins haven't, what pins have other functions multiplexed with them, and how to enable or disable those functions, or how to use them.

Until you consult the Datasheet, you don't realise that the 877A (keeping the thread in-topic) has COMPARATORS and a VOLTAGE-REFERENCE MODULE stuffed inside whilst the plain 877 hasn't - and how to recognise if the PIC on your desk can actually perform to do the task you're giving it, or if you should have bought a different variant.

So tell me - how are you going to discover those features UNLESS you READ the Datasheet? Crystal Ball? Telepathy? Oh... I forgot, of course - go the Datasheet substitute route and ask the forum!

C'mon, are you seriously suggesting that all the amateurs and hobbyists and students are excused from Datasheets because the experts and professionals - and those that can read - can provide all the answers?