So a really cool topic came up out of a long-dead one over at StudioArcanis, and it led to a damned good question being asked. I'm going to share both the question and the reply here, so as to record this for my readers who don't tend to hang out on forums.
"Wanderer are you suggesting a theory of magick that the older a symbol is and the more that it has been used, then the more efficacious it is?[...]"
"Sort of, but not quite so directly as that.
In my experience, three things matter when doing magic:
1) How established is that current?
2) How easy is it if for [b]you[/b] to get into that current?
3) Just how potent is that current capable of being?
And they really do matter in that order, for the most part.
Runes are ancient. We don't really know how old, but I suggest that you read Jan Fries' Helrunar, as it would indicate that there are some runic forms that go way, way back. Some of 'em were painted all over the world to boot, and usually that's for an unknown reason. Take what you will from that.
Age is only one factor in establishment of a faith, though. There are plenty of old systems that clearly didn't work all that well, as the cults did not survive. Those that were potent had pieces of themselves adopted by other, newer religions that still kept enough of the old ways to make it work (Sun Worship, anyone?). The fact that Christianity has survived and thrived may well be an indicator of just how robust it is as a religious system, even if its one I don't find particular resonance with.
Establishing a faith/system and keeping it going for thousands of years requires quite a bit of human interaction with said system. Furthermore, one could argue that it would require a fair deal of deific interaction too, so as to keep its tenants from being forgotten. When that happens, "grooves" are formed along human consciousness, and what your ancestors did is often easier for you to do. We can posit this theory because mice have been proven to inherit fear-based responses to stimuli like the smell of cherry blossoms (link).
The more something was done before, the easier it is to do again (theoretically speaking, anyway). This is why the status & establishment of a system matters.
Next up, we've got the point of "well, just how easy is it for you to get into that current?", and that goes along the lines of what I mentioned above. If your ancestors did it and you inherited genes that have those spiritual tendencies of theirs locked away therein, then it should logically be easier for you to get a sense of what they did and do it yourself. Likewise, your practices could well be inherited by your kids, provided you got into those practices before they were born.
If this is indeed true (and it appears to be, per science), then those whose families have practiced magical work for generations are going to have a leg up on others, so long as they follow the same line of study.
Finally, we've got the matter of power. How powerful can that system actually be? We've all heard stories of people levitating, crushing others under the weight of their psychic blows, and so on and so forth. These 'miracles' are said to have occur, but hearsay doesn't matter at this point; what matters is actualization. And whose to say how powerful a system is at the end of the day? That's a matter of crafting theories based on tons of resarch.
And here's the particularly important part about the 3rd piece of this puzzle: the pinnacle only matters if you can attune yourself to the system so effectively that you can actually utilize and channel the current at its full potency. If you can't do that, the glittering peak of power-in-a-system means nada to you.
.....and then you get into points of contention like "does this deity still exist?" and "is this accessible?". Some deities & spirits just won't like you regardless of what you do. Its not "fair", but "fair" is bollocks.
Its also worth noting that new systems can be damned powerful if based enough around old systems. I'm convinced that's why New Avatar Power works so damned well...our ancestors wouldn't have had the time to run around with a special dagger, tiger skin belt, and so on. They would have used the down, dirty, and quick way so as to fire their magics off quickly, without fanfare. Hushed, rapid whispers make more sense over grandiose conjurations if you look to history."
Continuing on, this is a topic I've asked spirits about, researched endlessly, and obsessed over for years and years and years now. Its a curious question to posit, but one with a potentially incredible impact. If we're being honest, doing magical work is about results. Would you agree?
If that is the case & success is your goal, adopting a system most prone to get you results is key. And no, I'm not recommending blindly following someone purely because they have the oldest magical system on the books - that would be idiocy. Instead, I suggest that success should be thy proof a la Crowley.
To that end, constantly tinkering with and trying new-to-you systems would be wise. As would integrating truths you find from different places and things.
We would be foolish to believe that these old systems have survived unmolested, and so piecing them back together and distilling them until we've found the absolute heart of the practice is incredibly important.
That is what I do, day in and day out. It is a passion of mine. Maybe it can become a passion of yours. ;)