I have the following (simplistic) structure set up in GnuCash, but this should apply to other software too:
Assets Bank account Pension Income Salary Interest
Every month, my salary is split between my bank account and my pension. Both assets go up in value over time, but the pension can also obviously go down, as it's represented as various shares.
It is simple to record the changing value of my bank account; every time I receive an interest payment (of a few pennies!), I add it to the total. But how should I represent the changing value of my pension? Should I add "interest" every year, or periodically at another time? Or should I not bother and just allow the account to become more and more out of line with the actual value of the fund, and adjust when I withdraw from it?