It really is confusing at first! As helpful as this board is (truly, truly LOVE it), it can be intimidating--so I get what you're saying!
When I first read about people obsessively planning and fretting over reservations, it made me think it was nearly impossible to get what you want, let alone at a time you want. The dining plan is overwhelming FOR ME. Others love it and wouldn't travel there without it. I see people posting their breakfast-lunch-dinner reservations and it makes my tummy hurt! It's just too much. Don't even get me started on the time issue. Planning my days around eating at restaurants is not a good time FOR ME. Vacation needs to be more spontaneous for my family.
I make reservations at the key places we don't want to miss. We leave on Friday for a week. We've got spots at Prime Time Cafe, O'Hana, Akershus, Park Faire. We'll have 3 girls with us (older "girls", 22 y.o.) who are there to run the Princess Marathon. We have several days without any reservations at all. One day we'll be at Universal to see Harry Potter. Another day at Kennedy Space Center. We like to break it up a bit.
When we're at Disney though, especially Epcot, there are so many food options. We love stopping at the different countries and getting things along the way throughout the day.
Again, this plan may not work for others, but it does for us. We hit the places we don't want to miss. This means me spending some time making the ADR, sometimes unsuccessfully and trying back another time. I typically end up getting what we want. If I don't, there are so many other choices.
We go to
Disneyland more often than WDW since we live in Seattle. Believe me, dining choices there are no where near as great or varied as WDW. We are in Orlando twice a year and find that if we don't go somewhere we really want to this time, we'll get it next time.
Akershus was the big desire this trip since we'll have 3 girls who grew up loving Disney and all the princess stuff. I'm really looking forward to that meal.
Don't sweat the reservation thing. Don't buy the dining plan unless you really enjoy anchoring your entire stay around food and reservations. Do what works for you and your family. You'll be so much happier.