For a bookkeeper this isn't difficult if we have all of your information to hand but we find that some people struggle with the intricacies of the return. As result they spend too much valuable time completing the documentation. Often people aren't aware of things that can be claimed against their tax bill and they end up paying too much tax. 

 

Self assessments also are rarely top of your priority list so they tend to get left to the last minute and if late this can result in a fine. 

 

If you have a good bookkeeper they will make sure you meet the deadline and you have the funds to pay your tax and thereby maximise the tax allowances that are available to you.