Something I mention a few times in Six Ways is about certain aspects magic being not generally important, but possibly being specifically important. I'd like to go a bit further than I did in the book into this concept.
Things that are generally important will impact the effectiveness of most kinds of magic. These are pretty few and far between, but they will be relevant to almost everyone. So perhaps 'having a clear intention', or ideas of contagion, spiritual cleansing, or of not working at cross-purposes to ourselves are generally important. Being respectful of the other beings we work with is also in this category.
Things that are specifically important are many, but who they actually impact are few. So your tradition may require the use of specific tools, sigils, gods, or spirits, or may require you to wear certain colors or types of clothing during a ritual, or to wear none at all. If you are a neo-pagan, the Wheel of the Year might be specifically important to you, and a Thelemite will likewise place specific importance on the Book of the Law.
My approach in Six Ways is to try to focus on the generally important aspects and to let each practitioner decide on all of the specifics for themselves, either based on their particular tradition or personal inclinations. This approach allows the most freedom of movement for the individual, and hopefully, the widest field of communication between practitioners. I have no difficulty talking to anyone about the general aspects of magic- you may be a Wiccan, a Thelemite, a Satanist (of any bent), an atheist, or a Buddhist and we can talk! These are all specific stances and come with their own specific sets of beliefs, taboos, rules, and the like. Now as a non-religious practitioner, I might not want to talk to you about the specifics of your religion, but we can absolutely talk about magic, and even work it together. Unless, of course you have a specific requirement that we be on the exact same page about the religious aspect.
Being that I work with spirits in general, I can also do work on the talismanic front for you that is connected to your gods, even if I do not normally work with them! If you have read the book, you may recall where I mention that one aspect of magic is developing 'special skills and talents'? This is one of mine.
To carry this out a bit further, it is generally important to actually do the work of magic, be that ritual, contemplation, trance, divination or spells. It is nearly always ok to modify that work to make it successful in your unique situation, unless this sets you at cross purposes with your tradition and this is a problem for you. So if I suggest the use of incense and you can't manage smoke, don't worry about it. Forget the incense! Perhaps use a scented oil, or hydrosol, or the like. If you are too sensitive to smells (or perhaps are just generally environmentally sensitive) forego all the scented stuff! You could build a 100% effective practice based on pen, paper, and clear water. Or maybe carved sticks and mud, which actually sounds like really good fun to me! I can 100% guarantee that if I ended up paralyzed or in prison, I'd be doing trance work and not much else and do just fine, without books, incense, or materia of any kind. It's not my preference, but it's a totally valid option.
Is there value to the more specific approaches? Absolutely! Is there value in sourcing potent, custom made or custom materia (or talismans!)? No question. But much like the folks who say that there is no point working out with weights if you don't do heavy squats and deadlifts (is this true for people without the use of their legs? Or with spinal injuries?), it is far too easy to let the specifically important things derail those that are actually, truly import ones. There is always another approach or workaround. In my view, it is always best to remain focused on the roads we choose to walk, rather than on the shoes we wear to walk them. Unless, of course, the shoes are of specific importance to your path, which they may very well be!