Invoice Numbering

What is your best invoice format that works for you.
Can I change how I set invoice numbering once we start new tax year (6th April)?
If for example I create invoice: #001, #002 and so on, can I start on 6th April (new tax year) again from #001, #002 ....? Since the year on invoice will be different ? or would be better to set up as #2015/001, #2015/002 etc. once we reach 2016 let's say from December: to set up again #2016/001 argh... i think it might cause confusion again 😉
That's why i need your help what is your way and how you keep everything organize and under control. 🙂