As of today I have crashed my drone 4 times. I crashed the drone 2 times because of hitting a tree. I hit the drone on a cement wall and it crashed on a cement surface at around 3 feet twice also. I would just like to know if I need to have it checked in a service center even if everything seems to be working fine. Thanks!

You should sync your flight to dji cloud and contact support@dji.com, contact a moderator here if you can they may get dji engineers to take a look at your log, before you ship it.
Hope it's ok.

If you haven't already done so I'd recommend discarding the propellers that were in use at the time of the crashes and replacing them with new ones. I'd also recommend extra caution when flying for a while but no, if it still seems to be functioning correctly then I probably wouldn't encourage you to send it to DJI.

Did the drone hurt? Since the drone had been crashed for 4 times, I recommend contacting to our support: support@DJI.com  your case. It would be better to send the drone in for an overall checking.

As of now I changed the propellers but now I noticed it flying to the right and then if I steer it back to the left it will then drift to the left. I already sent it to DJI.

Jlg Posted at 2017-8-23 19:17
As of now I changed the propellers but now I noticed it flying to the right and then if I steer it back to the left it will then drift to the left. I already sent it to DJI.

We'll take care of the drone after it arrived, should you have any further questions about this case, please provide us with the case number, we'd like to check it for you.