Almost all Chambers will use diary software to record cases and financial information. It can be helpful to keep your own spreadsheet or other record of the work you have done. This is helpful so that you have a note of when you completed a piece of work and sent it out, when you were paid for work, the hours you spent on the work, and the sort of work it was. You will find this invaluable if you are instructed on the same case again in the future. It can also be helpful for matters such as filling in your BMIF return.
It is also an obligation under the BSB Handbook rC87 to ensure that your practice is efficiently and properly administered and that proper records of your practice are kept. rC88 also provides that you must have adequate records to support the fees charged in any case, so having an accurate record of the hours you have spent will stand you in good stead in case of any dispute.