DB13-Frequence for Scheduling Job 'Update statistics'

Dears,

Currently we sheduled job 'Update statistics' in DB13 for our SAP production system  on every Sunday,

I don't know is it enough ? Do we need run it for everyday ?

Before there is a talble(NAST) accessing speed is very slowly in PRD but very fast in QAS system,

I checked update statistics job is scheduled in QAS on everyday, but I think the result is same as run the job in PRD system on every Sunday.

Now there is another table(VBOX) in PRD system is also accessing very slowly but in QAS system is very fast, is it related with the frequency of job 'Update statistics' ?

Thanks,

Michael