In my opinion, kit rods are a good way to get started. If it's your first try at building a rod, what could be better than to have everything you need right in front of you? However, many of the components that come in these kits (line guides, reel seats, grips, etc) aren't nearly as good in quality as the components used on the same rod you'd find for sale in a catalog or fly shop.
Generally there are two reasons why an angler decides to build their own rods:
1.) They are the do-it-yourself type of person & they like to tinker at a workbench. They tie their own flies, maybe make their own fly boxes, & other fly fishing accessories. For this group, building a fly rod can be a fun hobby & maybe a way to pass away those long winter months.
2.) They are the thrifty angler, trying to save a few bucks. They see where the price of a kit rod is about half of the factory-made rod. This isn't so much a hobby as it is a way to get a better rod at a substantially lower cost - even if it means they have to do the work. Many times the thinking here is 'hey, I can get the same rod at half the price if I just put it together myself'.
Well now, there's always a catch, isn't there? What both types of rod builders come to quickly realize is that the first rod they make is not as good, or as nice, as they had hoped. It doesn't take long to find out that getting the wraps just right, or the finish just so is something that's going to take a lot more time & practice. In rod building, that translates to making more rods - which of course means more money.
For those that like to tinker, that might be okay but it's certainly NOT for those that were attempting to save money. Even after you've practiced enough to get the rod aesthetics right, you begin to look closer at the quality of the rod components like the reel seat, grip, line guides, etc. On your next rod you start to branch out to include better (& more expensive) rod parts.
Now, how much money have you saved? How much has that rod really cost you? How long has all this taken - & you might still not have the rod you'd hoped for? We haven't even begun to talk about the tools & equipment you need (especially for those that want to make their own bamboo blanks), or the research & learning you have to do to get good at this, all the books you'll need to read & the questions you need to ask.....
Now consider that a professional rod maker has already put that time & money into their rods. Good rod makers are aware of all the different components out there - along with which ones are best for your rod & how to use them.
So ultimately, when you want the best rod possible, employing a rod maker saves you both time & money. You get the benefit of their experiences & knowledge. Plus you can have a hand in the design of the rod, having it made to your specifications. The bottom line is that you end up with the rod you wanted & most likely within your budget - & you didn't even have to buy any tools or break a sweat making the rod.
For those of you who want to try your hand at building your own fly rod, I encourage you to do it. Just don't enter into it with the false idea that it will save you time &/or money. The most expensive rod I ever made was my first & not because I could sell it for anywhere near what it cost me to make. No one would pay that much for that rod!! It will take years of hard work & practice to make a rod that actually costs you many times more than what you could have bought it for. So if you're going to try - try it because you want to, not because you think you'll save a few bucks.