Becoming a saddle fitter was a mid-life career change for me. I'd been an "at home mom" for about 5 years before I started working for Edie, and before that, I'd spent about 15 years making my living as a dressage trainer and instructor. And when I'm doing saddle fitting, I find that my trainer / instructor past is never far away. Many times, I have to keep myself from slipping back into the instructor's role if I see someone posting ahead of the motion or struggling with a transition or allowing the horse to lean on the inside aids. Having an eye for a rider's issues can be a help when choosing a saddle ... but old habits do die hard.
In the previous entry, Edie mentioned riders looking for a "miracle" saddle, and that's not as uncommon as many people would think. Our society's search for instant gratification is definitely manifest in the horse world - we want everything yesterday. We race Thoroughbreds that have just turned two years old; have 4 year old dressage horses that are showing First level and schooling Second; we start horses over fences at 3, show yearlings in longe line classes ... and want to find the magic saddle that automatically make our balance perfect, our seat independent and secure, our hands light and soft, and our aids perfectly timed and impeccably applied. (It's also supposed to turn our horses into Ahlerich or Giltedge or Abdullah or Rugged Lark ... but I won't get into that now.)
Here's the bottom line, people: there is no magic bullet. You must learn to ride, and ride well. I'm not talking about becoming professional or Olympic caliber; I understand the physical and mental limitations that we all face (yeah, even you young skinny types who bounce when you get dumped rather than just going "splat"). I mean doing your personal best and gaining a solid level of competence - becoming a rider instead of a passenger. I'll be the first to admit that the right saddle can really help your position and balance, and the wrong one can hinder the same, but there is no saddle out there that will make up for deficiencies in your riding. Deep seats, big calf blocks, grippy seat leather, padded flaps and steroidal thigh blocks will not turn an inexperienced (or - let's be blunt - lazy) rider into a competent, experienced rider. The only thing that will do that is practice ... and lots of it.
Why become competent? Besides the obvious - taking pride in the ability to ride well - there are two reasons: first, it's a lot easier on your horse. Anyone who's ever carried an unbalanced toddler on their back can empathize with a horse that has to carry an unbalanced rider. If you're consistently sitting heavily to one side, if your core muscles are lacking and you're unstable in the saddle, if you don't develop a soft, independent seat and hands, your horse - AND your horse's performance - will pay for it. You'll have a horse who's impossible to bend in one direction or the other, who drops behind or goes above the bit, who'll only pick up one lead, who'll duck out at fences, who'll go down the trail with his back hollow and his head in your face, who'll refuse to engage his haunches and work through his back ... I'm sure you get the idea. In order for your horse to develop correctly - or at least be comfortable - you must become a competent rider.
Second, it's easier on your saddle. I've seen "sided" riders who compress the flocking unevenly and stretch their stirrup leathers ... and that's just the tip of the iceburg. I've also seen sided riders stretch the panel and seat leather. I've seen riders who use an unholy amount of seat wear holes in or stretch the seat leather. I've seen riders twist saddle trees by constantly riding with one side further forward. I've seen tight legs warp or wear through flaps, I've seen riders who depend that "rider glue" - Sadl-Tite is one - compromise the finish of their leather, and in one memorable case, a rider whose dependence on "grippy" full seat breeches completely trashed the seat on her saddle - chewed all the way through to the foam - in about 3 years.
I guess it comes down to where you prefer to spend your money and time: in the saddle working to improve your riding ... or on the ground, with your vet and saddle fitter.