My skills are in the advanced beginner range (3 in a 1-9 scale).
On the E5 (6S) spinning 556/96 blades at governed 2,406rpm with the 1:4.0 ratio, it consumes around 544mah/min with 4500mah packs, and around 560mah/min with 5000mah packs. So, in theory, I can fly 06:37 min with the 4500mah packs or 07:09 min with the 5000mah packs before I get to 80%. I like to keep my flights between 05:00 and 05:30 minutes, so the smaller packs work well for me. I also find the helicopter more nimble with the 4400mah and 4500mah packs when compared to the 5000mah packs.
On the E5s (12S) spinning 606/96 blades at governed 2160rpm with the 1:4.5 ratio, it consumes around 316mah/min per pack (632mah/min for both packs) when using 3300mah packs. I could theoretically fly for 08:21 min before hitting the 80% mark. Again, because I like to keep my flights under 6 minutes, I may try smaller 3000mah packs in the future.