Precision rifles are just as addictive as drugs. I am not sure but strongly believe gunpowder is a refined byproduct of crack.
And the worst part is that it is not just the rifle that is spendy, there is the scope , then the loading gear, and ofcourse to have only 1 means it is lonely in the safe, so you need to build another 1 to keep it company, and then you realize that there are other calibers that merit use, so in no time you have 3, and everyone knows 3 will never get along, so yet another 1 is required to keep peace and harmony in the safe.
And lets not forget that a custom precision rifle seems to require the most expensive components available.
Custom rifles are expensive, and only the buyer can determine if the investment is worthwhile. The biggest problem is that the first custom build you will probably get wrong. You will pick the wrong cartridge, choose to heavy a barrel (or too light), get a stock that doesn't quite feel they way you thought it should, and get a scope that turns out to be unsuitable for your purposes. Then you'll sell this boat anchor at a loss and start again.
One of my custom guns is a M-7 in .243, lets just say that this rifle isn't perfect. The 22" medium weight Lilja barrel has decent balance, and it's not a bad rifle to carry around, but with a 1:10 twist I can't shoot match bullets heavier than 95 grs, and I've tried. The results were quite disheartening. The B&C stock feels clubby, and the shape of the pistol grip is such that I have to put conscious effort into each shot so as not to "drag wood" and pull the shot to the right. Someday I'll improve it, or just start again with another action, and hang this one on the wall as an example of how not to do it. In this case my pal's off the rack fly weight Weatherby MK V .25/06 was more accurate, easier to carry, easier to shoot, more versatile and nicer to look at.
I consider myself lucky though. That M-7 didn't cost a fraction of what my .308 or my .375 cost, and both of these rifles and my wife's semi-custom .30/06 Husky are near perfection for my/our purposes, although they might not be for you. The key to success in choosing the components for your custom rifle is to know what it is you want before you start. Everyone wants an accurate rifle, but if your custom build is to be used for hunting as well as range work, does it need to weigh 20 pounds? If you choose a fixed 30X scope for long range work, have you thought about how you will deal with mirage? Yet a pair of fixed power scopes, one low power and the other high might be a better investment for you than an expensive variable from Nightforce or S&B. If you chose an economy target or worse yet tactical scope, are the adjustments accurate out at their limits and are they repeatable. Did you choose a powerful cartridge (.30-378, .338 Lapua, .408 CheyTac, etc) for its long range performance without regard to the cost of components, or to the effects the recoil might have on your shooting? Did you make sure that the stock of your dreams will fit you, that is suitable for the weight of the barreled action, and that the comb is a suitable height for your sights. Have you actually tried a 2 oz trigger before you ordered one?
The more you shoot and the longer you shoot, the better you will understand what you need, therefore I would consider a custom rifle a mistake for the entry level shooter. There are not many shooting disciplines that are not catered to with off the rack guns, so shoot one of them and make a list of what you would like to change and why. Then decide if you should just tweak your off the shelf rifle, or go for a full blown custom rifle.