After thinking about making after-tax retirement contributions, I thought today - Heh, I'm not even making the maximum pre-tax contributions. I've been making about $A28k a year in pre-tax contributions. Actually, that is supposedly my employer's contribution. In the university sector in Australia, employers contribute 17% on top of the nominal salary to superannuation for continuing (=permanent) employees, as opposed to the minimum government requirement of 9.5%. The maximum pre-tax contributions allowed for over 50's currently is $A35k per year ($A30k for under 50s). So, I just submitted the form to add $100 a week to my contributions. I didn't totally max things out to allow for a year or two of growth in salary before having to submit another form.
By the way, the standard agreement in the higher education sector includes another 8.5% pre-tax contribution from the employee's salary. I already opted out of that, because it would have been over the concessionary limit already when I started in 2011, when the concession limit was $A25k a year. Actually, I already had to withdraw an excess contribution to superannuation last year, which was a hassle, before the contribution limit was raised.
I'm still thinking about post-tax contributions. If I do it, I think I will start small at say $A1000 per month. That is small compared to the limit of $A15k per month :)