Good Enough for Chair Work?

The construction of a windsor chair offers a great deal of opportunity for, shall we say, imperfect construction. The flexibility of the wood and the genius of the design (developed over centuries) can make a series of imperfect parts and joints add up to one nice chair. This is one of the enticing things about first learning to make chairs. They are complex enough without throwing "perfection" into the mix. This is all fine, as long as it doesn't develop into bad habits that become limitations. I have seen all sorts of techniques that work, but that in my view have no future. By this, I mean, that while they may serve the purpose for which they are being employed, they will not serve to advance ones skills, abilities or understanding.
The picture that I've posted is of the drilling set up that I use for all of my mortises into legs, arms etc... It's a good example of a technique that has grown with my abilities and designs. The V notched holders in the vise keep the workpiece perfectly parallel to the bench top on which rests my angle tool, square, and mirrors. By positioning myself during drilling so that I can glance from one mirror to the other, I drill with great accuracy. Now why be so accurate?
In my early work with undercarraiges, I began to use this set up even though it may have seemed like overkill. I can hear the voices now, "I just set up a bevel gauge and shoot!" Maybe so, but now, when I am drilling the mortises for my rodback duckbill joints, where I drill the shoulder with a forstner bit and the mortise will a bradpoint and both must align "perfectly", I am glad that I didn't stop at "good enough". The minute that it takes me to set up is well worth the accuracy gained and the advances in skill and design that come with it. I like to remind myself that another minute spent making a better chair is insignifigant in view of the centuries that I hope that the chair will endure.