Aw guys don't be such wimps!
I used fertilizer on my old Nep collection and it really works wonders. I used Gro More brand Urea Free ("non burning") orchid fertilizers, mainly the 20-20-20 Tropical Gro blend (including micro nutrients/trace elements) but on occasion I ran some of the Gro More Cymbidium Bloom formula (10-30-30). I'm not sure if it's what helped spur blooms on the Neps I've gotten to bloom or not but it certainly didn't kill them. Just go lightly, 1/4 strength of the label recommendation at first and be sure to do several pot flushes with pure water between each fertilizer watering. Basically treating them like Orchids is OK as long as you exercise restraint with how much you're using and use proper fertilizers for delicate plants.
If you fertilize be sure to feed the pitchers with dried or frozen crickets so the plant doesn't see a reason to quit making pitchers and start to rely on the fertilizer. Cos they will take the easy way out if you let them, they will grow into a vine but not make a single pitcher along the way. If you continue to feed them along with lightly fertilizing they will not quit pitchering, That is provided it was pitchering before you began fertilizing, fertilizer improves already robust plant growth/pitchering but it will not make the lights brighter or the air more humid. Proper conditions go a long way to speeding up growth. A small cricket into each active pitcher on a weekly basis is a good regimen, when the cricket looks to be dissolved or sinks to the bottom feed it another, on tiny plants you'll have to check the shadows through the side of the pitcher and be conservative on prey item size. The "Small" size crickets at Petsmart are generally good for 4" plants with 2-4" pitchers. I would crush the cricket with the feeding tongs and then gently shake the pitcher once it's in the fluid.
Back to ferts, be sure to look for non burning fertilizers used specifically for orchids, not roses, vegetables, Bromilads or pine trees... orchids! These tend to already be gentler and if used sparingly it's hard to go overboard with them. If you don't find what you want at stores look on the web. Infact, before you buy check the reputation of the brand you're looking at buying on the web first. It doesn't have to be Gro More that's just the brand that they sell at the local Orchid shop and so it's the one I use for all my various plants and soon HL Neps again!
Dyna Grow & Dyna Bloom are also decent fertilizer but being a liquid it's kind of a rip off compared to Gro More which is a blue or green powder that can be mixed into your watering water a couple times a month. 1 lb of powder lasts almost indefinitely. My Neps also got foliar feeds because I would be spraying the orchids mounted on the back and side walls of the grow chambers on a weekly basis and the garden sprayer tends to spray everything in it's path.
Like anything start out with one or two plants you can use as test subjects with the particular fertilizer you choose and see what happens. I'm quite sure you'll be pleasantly surprised with the results. Why grow a seedling/tiny clone for 5 years when you can have a adult sized or flowering plant in 2 or 3?
I never did use coffee (N) or tobacco ashes (P) on my plants. I'm sort of concerned it might lead to mould/fungal attacks of some kind or simply just stinky pots, but maybe those fears are unfounded. Powders are clean and no smell.