Academia, or UPG or a mix of both

I also use a combination of both, with the background of archaeology and mythology to help sort out things I get via UPG and to try to discern which might be actual connection and which parts are just in my mind. I believe the gods can grow and learn (just like humans) and, from those experiences, even change (just like humans), so things that might not be strictly grounded in lore are not necessarily wrong, given the area, history, situation, new info, etc. The idea of a static and eternally unchanging deity is, to me, unnatural and frankly kind of terrifying. If humans can grow and change and deities couldn't, that would call for a severe re-evaluation of the basis of the relationships between the two. Growth and change make for continual improvement; I just can't see that humans could be capable of that and deities couldn't be.

To me, academia and UPG are equally important. You have to keep in mind that mythic narratives, poems and archaeological traces are expressions of past experiences with the Gods and devotion towards Them, even if the preservation of those pieces of information is often far from ideal. Just like I resort to teachers and experienced people whenever I want to learn something, when I want to know the Gods I naturally resort to the work of their past worshipers. Why I should I neglect their expressions of faith and devotion just because they lived hundreds of years ago? It doesn't mean I have to do everything they did or limit myself to it: the world has changed tremendously, yes, and there are a lot of gaps, but I'm not paying tribute to new gods. I'm worshiping old gods and as such I like to know what was done for Them in the old days. I need a solid basis from where to start and, as I see it, there's no better starting point than the experience and devotion of those who actively honoured Them in the ancient world.

Of course, following what Conor said, reconstructionism is a methodology and not a goal in itself. I'm not re-enacting a religion, but giving new life to it. Which means that I'll naturally have to take into account the modern context and the needs of today's life, not to mention filling in the gaps. And any living cult will change as things around it evolve and people add in their personal experiences with the Gods. That's where UPG comes in. That's its role.

Living religion is simultaneously traditionalist and innovative. It preserves and transmits old lore and practices, while at the same time adapting them and innovating. It's a building under constant renovation, but it starts somewhere, out of foundations that resonate throughout the entire structure. If it's not rooted, it collapses and is constantly being started anew; if it doesn't move past the foundations, it will never grow into a proper building. We need both academia and UPG to be rooted in the past and grow strong in the present. At least the way I see it.

To me, scholarship provides the base recipe, while UPG gives it flavor.

Following UPG I almost invariably go search the literature to try and look for other precedents and get context. Yes, I apply the scientific method to religion... but to be fair that's actually an integral part of my faith. I work with a Daeva whose name does not appear anywhere in the literature, but he's strongly steered me towards being scholarly. Even if I do not worship as is done in the past, I'm expected to fully justify why I don't and cite examples to support my argument. I've wound up stupidly well educated about a lot of other traditions, but very little of it is directly relevant to my own practice, it's quite strange really. On the other hand, the amount of times when UPG and archeology line up has been startling - I wonder if I'll not eventually find my practices aren't dissimilar to those in the past after all?

I'm totally curious now, as to who the Daeva is?  Perks ears.

I use a combination of both as well. I like knowing the historical precedents, because it helps me get to know a god better, but it's not the same as experience with that god, which is where UPG comes in. They feed off each other, I think, because once you know what to look for, it's easier to understand messages and other things you might get. You can understand the epithets and aspects of a deity and how they were worshipped, which may be relevant to your own experiences. That's how I generally approach it.