I second larrabee's recommendation of doing the Life in the UK test sooner rather than later.
As you said, you'll need to study. Living in the UK ironically isn't enough for the Life in the UK test. There are topics that you won't know just from living in the UK, even for 16 years. Buy the book, read it through and you should be fine. Most pass the first time, but you do need to read through the book.
Everyone's got different reasons for getting or not getting UK citizenship.
My main reason for getting it was to never have to worry about UK immigration again. ILR expires if you're living out of the UK more than two years. We have no plans to live out of the UK now, but we never know where life may lead.
It's also never going to get easier or cheaper to get UK citizenship now. It's only going to get more expensive.
I figured it was best to get it as soon as I was eligible since I met the criteria and couldn't think of a reason not to. It is a big chunk of change, but worth it for me.
Being able to vote in the EU ref and in the upcoming election makes me feel like I finally have a say in UK immigration (and so much else). After years of being here on a visa and having to follow UKBA/UKVI's rules without any say, I can finally give a little voice for immigrants.
Also, we can travel more freely in the EU as UKCs.... at least for now. DH and I took advantage of that recently and spent 6 months travelling through Italy, France and Germany.
Good luck getting all your papers together! It's good you're getting started early rather than having a last-minute panic.