Yes you do get used to it, but unless it's light chop, you shouldn't really be standing/moving in it either.
It should be a judgment call: The Captain's initially, and then if he gives permission to continue working, down to the crew. The ride can often be much worse at the rear than at the front, and that can be easy for us to forget. If in doubt, err on the side of caution and sit down - nobody's gin & tonic is worth an injury.
Many crew don't realise that turbulence is a crew killer - if you read the stats on inflight emergencies that include a breakdown of fatalities/injuries (Flight International may still publish them) you quickly note that a disproportionate volume are to Cabin Crew. I insist that the galleys on my flights are secure (latches down & carts stowed) throughout the flight, and get stroppy with crew ehen they are not. Anyone who has been in moderate/severe will know why.