The reason behind the 8-12 month is the stability of the tank. During the first year your tank is going to go through changes and will mature. You don't want to put an anemone in a new tank. They don't tolerate changes very well. Also it gives you time to get over the "new tank syndrome".
Base rock is a lot cheaper then LR
and it will become live rock over time. You will still need to get some LR
but you don't have to spend the money to get all LR
I have about 250lbs of LR
in my tank and another 100 or so lbs in my sump/fuge. I run a skimmer and off and on I will run carbon just to polish the water. I run my carbon in a phosban reactor. Regular PWCs, enough LR
and a skimmer are pretty much all you need to filter your system. I like using a refugium to help battle excess nutrients, they have many benefits to a reef tank but that is another topic.