Number Range leading practice for Incidents, Problems, Knowledge Articles

Hi Experts,

We're currently implementing Incident , Problem & Knowledge Management [i.e. via crm_ui] as part of our SolMan 7.1 upgrade. My question is: what are leading practices for designating number ranges for each of these?

Should we (a) start with '000000001', (b) start each type with a different initial # e.g. Incidents '100000001'/ Problems '2000000001' etc, (c) or stay with our current series for RFCs & Change Types that all start with '8...'?

Your insights would be much appreciated.

Darryl Michael