As an INFJ scientist, I rely on my tertiary Ti a great deal and have developed it to a high degree. However, there is a heavy price to pay for overusing the tertiary, which is that it can lead to inferior function burnout. You mention your own experience of Fi burnout, so I'm sure you can relate.
My Se is also quite well developed, as my job requires painstaking attention to masses and masses of minute details. But too much abuse of my Ti/Se functions can trigger a full-blown inferior function reaction, much like those described by Naomi Quenk in her book about the Inferior Function.
When this happens, I suddenly become very obsessive and anal about details and can no longer see the wood for the trees. I become incapable of making decisions. I may get totally "stuck" on sensory processing - surfing the net for hours or playing computer games or mindlessly watching TV or overindulging in food or alcohol. Even though this is neither pleasant nor enjoyable, I cannot seem to stop until I basically collapse from exhaustion. I lose all track of time and neglect my responsibilities. If I'm in company, I may babble on endlessly about whatever is obsessing me. I may be unable to sleep from overstimulation, so the next day may be even worse.
Thankfully, I seem to have gotten a better balance in my life recently. If I remember to take time out to exercise my preferred Ni in some way (posting on this forum is one thing that seems to help), then I am less prone to these inferior blow-outs.
My point is this: we can indeed develop a high level of skill in our less-preferred functions, but we still have to be careful not to overuse them. They work best when used to serve and support our dominant/auxiliary combo, but they will flare out of control if we place them in charge instead of our natural preferences.
I also do all of these things, and I've noticed that periodically allowing myself to take a mental vacation whenever possible (let Ni lead for a while, for example a lengthy and strange daydream) helps a lot, but I hadn't recognized it for what it was...
"Don�t ask what the world needs. Ask what makes you come alive, and go do it. Because what the world needs is people who have come alive." - Howard Thurman
Personaly-WO. i know what this is. i'm havin a fat day. Si/Fe
everyone uses every function about evenly. take NE for example. if there are those who don't use it much, then why are there such massive amounts of people constantly flowing through Wallmart with 20 items or less?
*Agrees with Apollanuat* Scientific study really push you to develop Ti. I don't exactly experience Se burn out in being obsessed over details. I do have my occasional indulgence of games and good food though. Never to the point of collapse like that.
I have a good handle of my tertiary Ti, to the extent that many people see me as an NT. I suspect it probably takes me a tad longer to process info compared to a Ti dominant individual though. Nonetheless I still manage a thorough analysis.
The way I see all the functions is that they're merely tools. Some you're more familiar with using and the rest you need practice to be more adept at. Obviously the extend of your abilities with tertiary and inferior functions will never be as good as somebody with it as their dominant function, but you'll still be able to use it effectively at will for most things. You'll probably never be able to realize there are other subtle uses of the said function but you'll probably unconsciously substitute something else for it anyhow.
Se for me, I'm decent in selected areas. For example I'm very good at pinpointing and tracking objects and sounds. However if you ask me to discriminate subtle differences between two things it'll take me a lot of effort. I suppose it's really an interaction of Ni and Se. Tracking stuff doesn't really require me focusing on many details. Instead all I need is track selective things that Ni identifies as part of the pattern. It's also easier to "turn on" Se whenever I need it. That way it's less draining.
Yeah, I notice my Si when it comes to food. I'm really sensitive to how something should taste. I can tell when an ingredient is missing that should be included, or I can deconstruct the ingredients in a dish (if I am familiar with the individual flavors from the past).
People think I have this crazy sensitive palette, but I guess it is Si, haha. Or maybe it is both.
I don't know that much about the individual functions, so that's the only example I can think of for myself.
"Charlotte sometimes dreams a wall around herself. But it's always with love - So much love it looks like everything else. Charlotte Sometimes - So far away, glass sealed and pretty." - The Cure
There's a lot of natural tough T's I know who organize volunteer work, work in areas devoted to helping people, human-related jobs etc. They don't show their care explicitly, but they work a lot to improve the conditions of the people. Some talk of it analytically, others carefully describe the feelings, emotions and values related to the subject. They don't quite dive in the feelings, but they acknowledge how everything F makes their job worthwhile and gives it signifance.
Many of them like to tell how their work influenced others positively and what kind of feelings they had.
I've thought of it as an influence of feeling to choose a job that promotes F values, however technical or T it might be to actually do the job.