Best Time to Up My Tier

[Shhy]

My tier date is on the 9th of the month. What would be the best time to up my tier? Should I wait until after the 9th? Also is there a way to move land between groups without upping my tier?

[Bobbie Faulds]

I'd wait until just after the 9th. You get charged for the full amount of land you get. If you get more land even for one day prior to your date, you'll get charge the full amount for what you have. 

[Amethyst Jetaime]

Even if you donate your land to a group you are still responsible for paying the tier.  So sell go ahead and sell that land back to yourself (or get the group owner to if you can't) then deed it to the other group.