The Chelsea defender started the year playing for Owen Coyle at Bolton, but entering the final month he finds himself working for the newly-installed Rafa Benitez at Stamford Bridge.
Signed by Andre Villas-Boas in January, Cahill saw the Portuguese replaced by Roberto Di Matteo, who was then subsequently sacked with Benitez stepping in.
The 26-year-old's England appearances have come under Fabio Capello, Stuart Pearce and Roy Hodgson, leading Cahill to confess that making progress has been difficult.
"It has been a crazy year for both club and country," said Cahill. "It is different, but hopefully it is a case of biding my time and working hard to get in.
"The changes of managers is what it is and there is an element of obviously getting involved with one manager and then you are on trial again.
"Every manager has got a different opinion and I just have to keep working as hard as I can and hope you can impress people enough to be given a chance.
"I feel, for England especially, the few games I have played have gone very well over the course of the 12 caps I have got so far. And for Chelsea it has worked out better than I thought."
A regular squad member, Cahill has yet to establish himself as an England first-choice, but he feels that solid form for his club will put him in Roy Hodgson's sights.
"The manager has changed it around a lot, so it is a matter of playing well for Chelsea and trying to get my foot back in the door," Cahill added.
"I think there is definitely a spot available for a centre-back in the national team so I have just got to try to take that."