Those who have not looked for a job outside Big4, tends to hold the view that there is no good time to leave. I still remember my friend asking me if life outside Big4 is bad, when I am making more, working less, and doing things that I like.

Not saying that you can't make audit your profession. If you like it, stay in it. But there is no need to treat it as the One Job.

15 years is around partner/director level already (~300k). Very very rare stuck at SM unless voluntary

At this point the focus is on being equity partner already (350k-1m/annum). Compliance will never ever reach that superscale

There are people who are SM / director (my Big4 doesn't use this) for life and not voluntary. By then, they should have gone to commercial for the better pay/hour balance, but it takes a while for some of them to realize it (or to find a suitable one).

Are there any partners who are from commercial? I.e, maybe big 4 for the first few years, then to commercial then back to B4 as a partner?

then just go be a slave lor. just know that private-u and msia uni students are starting off at the same page as u when u grad hehe

If you like accounting role, B4 is a feasible route for you cause u can acquire experience auditing various major companies and at the same time prepare to clear the CA exam. Once three years is up and you have successfully obtained the relevant professional qualification, you may then move to a commercial entity to acquire commercial experience. The CA qualification shall place you in a distinct advantage position as you move up the corporate ladder, you should prepare yourself ready to assume senior financial position and double up as a company secretary. Under the company's act, the company secretary must be an accountant or a qualified lawyer. Eventually, you will have exposure to the board which may propel your career even further.

If you want to be a controller or finance manager in general in any decent MNC, no choice but to go through Big 4. It is the most straightforward route to take.

Back to Big4, straight as partner? Maybe for advisory roles, but less likely for audit.

If you mean went back straight as partner, it will mean a equivalent position switch (e.g. CFO to partner). Ignoring why would anyone make such a switch, the skillset and perspective are actually different. So don't think that will happen.

Why does anyone even think that by putting in the time you are guaranteed X rank in Y years? Plenty of scrubs are not even of the requisite calibre or end up dropping out halfway as they don't have the iron in them.