A colleague recently asked aunty Biscuit how long it takes her to knit a jumper.  Here is the vague timelines she replied with:-

Super chunky a few days t o a few weeks.

Chunky a few weeks to a few months.

Double knit a few months to a few years.

It has been noted that aran (the yarn not the island off Scotland) hasn’t been mentioned. Interrogation by Harrier who is trained in various techniques to obtain the truth has shown this to be a similar fit to the chunky timescales.

Harrier and I have extrapolated these results and conclude that 4 ply would take years to decades and that two or three ply is inadvisable for her.