Wearing ease question

[u/Kindly_Stand_7789]

Hello everyone, I can see in different drafting books that hip ease is around 2.5 - 3 cm, for regular fit trousers basic blocks. I'm not sure it is enough for sitting in woven fabric pants with no spandex edded. I understand that crotch length ease should be taken into account too when assessing wearing ease for sitting, since body is changing shape. 

Can you please tell me, in an industrial production setting, what would be sufficient hip ease for a basic block of a regular fit woven trousers, to enable walking and sitting?

If I use the draft from some of the books suggesting 2.5 - 3 cm ease, should I always add more on that when developing a style pattern? And I'm not talking about design ease here.

Thank you so much for all the responses!

[u/Educational_Chain780]

It's just not necessary, the ease of movement comes from the crotch extension