Talking of Acers.......

It's a living thing......Yes water.... Make sure the plants arnt standing in water.....ensure that excess water drains away this will help to stop the container from freezing and and only water when needed. .... Check weekly instead of daily

 

One of the best way to check if a plant needs watering is by picking it up and checking the weight....water the plant...let it drain off for an hour ...go back and pick it up.....check the weight... Go back a few days later ...check the weight.... If its light ... Water it.... If its same weight ... Leave it..... Whilst your checking the weight... You have the opportunity to check the rest of the plant over...for bugs disease etc.......
Be careful of your back whilst doing this. ...........