Benefit of running AppLocking service ?

Thanks for the great app for Android.
Is it necessary to run the AppLocking service all the time, even though I am not using Avast to lock any apps ?
I have disabled it from inside Avast settings, but the service still runs.

What are the uses for a persisitent UpdateService, MessageScannerService and Webshield service ?
My internet through 3G or Wifi is on only for very short periods over the day - would it be more efficient to just start and run the service once Wifi or 3G is switched on? then the service could shut down once internet is off ?
Message scanner service - is it possible to just scan the incoming message once an incoming message event is detected, instead of running a service 24 hrs a day ?
Update service - what does it update ? definitions ? I have disabled the automatic update of definitions, and do it manually. in this case should this service still be running ?

Someone might ask what I have against running a few services - they probably drain very little battery or RAM.
I am not sure if that is true, but on demand services seem to make more sense to me.
any explanations will help me understand.
thanks

Any answers about the running services, which are apparently not of use ?

Today I see a total of 6 services running
AppLockingService
AdvisorScanService
WebshieldService
UpdateService
OnDemandScanner
MessageScanner

AppLockingService triggers PIN security activities, not only application locking. It is running in backround (so you can see it, but for most time is in sleep mode).
AdvisorScanService - its purpose is to scan addons in new or updated applications, again, most of the time it is running in backround.
WebShieldService - very small one, just watches and scan URLs for malware or phishing (if turned on).
updateService - yes, this is for definitions, when turned off no regular check will be done (but is more safe to keep it running than kill it).
OnDemandScanner - this triggers scan in case of new application installation or update - you can turn it off in shields settings (is recommended to keep it running).
MessageScanner - service which scans incoming SMS messages - you can also turn it off in shield settings.