This is an interesting thread
I've been using VG plus peppermint oil as my main vape for nearly a year. So far I have never had to clean an atty, and I don't have any lung issues such as pneumonia.
Of course - YMMV.
I'd like to see a link to any info related to advisories on inhaling oils, please.
Notes
I use pure peppermint oil, undiluted or unthinned in any way.
My base liquid is Ecopure Krystal 36mg (basically VG pus some DW and EM I think).
My usual flavor percentage is about 5 to 10% for the oil - 1 or 2 drops to 20 drops of base, but occasionally more.
Other flavors I may add are tobacco, menthol, etc.
I only use 5 volts (standard 510 and 801 atties), and LR (a Tornado + LR atty).
I have never, ever, had to clean an atty (except after DIY liquid mess-ups of course). That's in a year of use, so I wouldn't describe myself as 'experienced', more time is needed for that - but a year with no need to clean an atty is a reasonable data source.
My atties all last months. In fact I can't remember the last time I blew one in use - but it would have been while dripping, or using a cart I knew needed topping up. Months ago at any rate.
I have super-sensitive lungs and have even had to spend a few days in hospital with a breathing problem, before I found ecigs. For example as soon as I go over 6 tobacco cigarettes per day, I am at risk of bronchitis, and always get it if my consumption goes up to 10 cigarettes a day.
I can't use PG as my lungs don't like it.
I don't have any lung issues after vaping a lot of peppermint oil for a year - except that my lungs are better than ever before, of course. My all-day vape normally has some peppermint oil in it.
But as I said - YMMV.
Roly
Paraffinoma note
There is a type of pneumonia caused by inhaling oils that no doubt causes some reluctance to vape oil-based flavors. It is called Lipid Pneumonia or 'Paraffinoma'.
However, this is caused, as far as I am aware, from inhaling mineral oils such as paraffin (kerosene) and possibly vegetable oils that are chemically very similar such as castor oil (which is so similar to mineral oils it's used as engine lube). This medical condition is the occupational disease of fire-eaters, as they breathe in paraffin fumes all the time. It is more commonly seen among the elderly or infants who take paraffin or similar over a long period of time for constipation, and breathe the fumes.
As far as I am aware there is no risk of paraffinoma from inhaling 'essential' oils, as there are apparently no cases on record, with a long history of inhalation of plant oils for various purposes such as application to body areas adjacent to the mouth/nose, and aromatherapy. The term 'lipid' in lipid pneumonia refers, apparently, to the resulting obstruction in the lungs that consists of fats (lipids) as well as infection. There are no lipids in the oils.
Please note this opinion is that of a layman after research of online materials. For a medical opinion you would need to speak with a bronchial consultant physician with experience of lipid pneumonia cases (which are rare).
Update
In general the term 'oil' used in the world of flavourings has no relationship to oils. In flavourings an oil can be called that because it looks oily (viscous) or other reasons. An 'oil' in the world of flavourings is likely to be a plant extract in ethanol etc, and may look oily but have no chemical relationship to the mineral oils that cause paraffin lung.
Also, the question of dosage needs to be addressed. Although it may be possible to contract paraffin lung from non-mineral oils (ghee or purified butter has been suggested as one cause in South Asian infants who are excessively fed with it), the dosages are huge by comparison with the tiny amount vaped as ~10% flavour in e-liquid.
