Eight years ago or there abouts I picked up the Incra LS17 and wonderfence. After years of bump and run, tap and clamp and countless other attempts at achieving the accuracy I desired I found it with the Incra product and I've never looked back. This is not to say that others have not used any number of methods to achieve similar results. What I would say is that for the novice attempting to achieve precision results the use of a micro adjustable rig is far superior to any other method and gives them a better chance at achieving desired results. There is not only a degree of accuracy that is inherent with experience, there is also a degree of expectation that comes with spending years honing ones skills.
You can get into the debate of what is close enough? Does the end product warrant the required effort? Is it worth attempting to get
within .010" or is .032 (1/32nd) or even .016 (1/64) close enough. The woodworker has to ask him/herself does it really matter? In all honesty the vast majority of projects the hobbyist woodworker takes on does not require much more than 1/32 and in some cases I'd venture to say that taking it to 1/64 is really pushing it in terms of do ya really need to try for it. My approach has always been to attempt to get it as close as possible. For me, that means working withing .010 or better if possible. In my opinion, tolerances tighter than .010 is beyond my equipment and my patience to achieve such numbers. I do have a couple of exceptions to that rule and that is when doing inlay work. There I attempt to make it as tight as I possibly can, without exception. Anytime I've used the excuse of "close enough" I've regretted it. If only for the fact that "I" knew it wasn't as good as I could have or should have gotten it. Glues and fillers can only hide so much. At least to my mind anyways. That don't make it right, that don't make it wrong, just makes it my way of going about things. I don't always achieve expected results, but it is rarely for the lack of trying!
At the router table, I'am all for micro adjustable lifts and fences. A partial turn of the thumb wheel or a couple clicks of the fence and I'm where I wanna be or damn close to it. A couple thousands wider in a dado to get that perfect fit or a little more depth for a rabbet are easily and accurately obtained. Recreating profiles exactly is alot easier and less time consuming. Dovetails and box joints are a snap (perhaps snap isn't the right word *L*) but very doable none the less. Double dovetails and double box joints become within range of the average woodworker. The WonderFence provides an offset for edge work. Does it rather well at that. Here the adjust ability is achieved via a sliding wedge system. The tall fence portion of the WonderFence is somewhat lacking IMHO. Don't get me wrong, it works, I just would rather prefer a solid high fence. When I built my table I installed a digital height gauge for the router. I can't tell ya the last time I used it. After a while, you kinda get tuned into these things and you end up working by eye. Kind of an oxymoron. Some aspects of working on the router table I've learned to do by eye having learned what to look for using the micro-adjust ability of the Incra system. A good question to ask ones self is just how much time does one expect to spend at the router table. Another good question is does one have a penchant for or the patience to learn such things.
Most equipment available today either has or has available an micro-adjustable feature. As much as you may like the idea, you gotta ask does it make good sense. Can you afford it (some of this stuff dont' come cheap) Will you use it after 6 weeks (ie my digital height gauge). Can you learn to achieve the results you desire without it. Do you have the time and patience to learn how to achieve those results. Will your typical project require the advantages of micro-adjust ability...etc. etc. etc... IF you spend little time at the router table, then I'd say the LS isn't the biggest bang for your buck. Perhaps the tablesaw, bandsaw, planer might be the place to spend your money if you must.
As a result of micro adjustments I've spent an awful lot less time sanding. And if you've ever has to sand down a couple thousands worth of sugar maple, you'll appreciate that little fact!! Again and again. And I"m one of those guys who doesn't mind sanding. I enjoy building chess tables with mirror finished tops. and if a little micro adjust ability can save me .015/.030 worth of sanding, then I"m all for it....I'd much rather spend a few hours working on the mirror finish than prepping the surface for hours on end.
Accumulated error: If you dont' know what it is, then you need to look it up..short version is if you have 6 pieces of wood that you want 3"s wide for a total of 18"s in the end. If you're off by .030 on all 6 pieces in total you'll be off .120, darn near an eighth of an inch. There are times when that eighth won't mean much if anything at all, then there are times when that eighth is going to be a big deal.
Then there is the proverbial argument "Wood Moves". Yep it does...but are you looking at radial movement? Tangential movement? Flatsawn or Quartersawn? The kind of wood itself makes a difference in amount of movement. How you laying out your wood? Is the environment the project is going to similar to the one in which it was built? Most projects can absorb that difference between the two without much to worry about. But if your building a curio in Atlanta Georgia for someone living in Arizona, then ya gotta pay attention. Compression is just as much a problem as expansion...you just gotta pay attention. There is a great deal to the whole wood movement thing, and it pays to at the very least have a fairly reasonable working knowledge of it. Especially as your projects become more complex. What ever the case may be, I fail to see the disadvantage of using any micro adjustable feature you may have available. There are several wood movement calculators available online. Well worth downloading one and having it handy
As I mentioned earlier, this is just my way of going about things. Some may see this as just a lot of blah, blah, blah..others may find it of some value. For those who do find some value in my 2cents worth here.. take the time to do your homework, ask yourself the hard questions and above all else..be honest with your answers. There is no one way of doing anything, let alone woodwork. Spend the time and effort to find the way that works best for you. If tapping your way to a couple of thousandths works, then go for it...if a few clicks here or a turn of a thumb wheel there does it, then go for that. Ultimately finding what works for you will make the time spent in the shop much, much more enjoyable...