I'd just purchased a refurbished laptop that comes with a 120 SSD. I am wondering if I need to upgrade it to 250gb. I am going to add a 500gb HHD with a caddy as my data drive (D

so there is no need for the SSD to hold the pictures, video or documents.
I reviewed what I have in my current laptop. The system folders including all the programs I run would take up about 75 to 80 GB of space. But the AppData on my current laptop is huge (150gb).
I wonder why is it so huge? Is there something I can remove to make it more nimble?
Back to my 120gb SSD. If I load all the programs I use and start using that "new" machine, would it run into program because of short of room as the appData gradually builds up?
This is a follow up to this thread.
First, I have to say I am extremely happy, so far, with the refurbished HP 8470p I purchased from a third part thru NewEggBusiness.com. The third party supplier is a certified refurbisher and did a decent job with the machine. I had a couple of questions and NewEgg did a good job into resolving them promptly. My wait time on the phone is less than a minute, and the supporting staff was able to give me answer within a few seconds. Very impressive.
The 8470p is a HP Elitebook. My daughter had one when she was with Gap and I recalled it was an amazing solid performer. She had Windows 7 and was loaded with corporate apps. The machine was a total over kill for what she did (some Excel worksheet and logging in the corporate server). Mine came with a 3rd generation i7 (same as my Toshiha S855), 8gb dram and a 120gb SSD.
This original post was about my concern if 120gb is good enough (after I add the 500gb HHD for data storage in the DVD bay). I upgraded to the latest Windows 10 and then cleaned out the Windows.old folder. I installed/downloaded all the apps and programs I used. I had just completed the installations and I still have 69gb free, of the 117gb SSD. I think it is a comfortable margin at this point to leave the 120gb SSD alone without upgrading it. I will monitor the drive space as I started to use the machine progressively.
There was a pleasant surprise with this HP. I had a HP laptop quite a few years ago. When I sold it, I took out the HP Expresscard adapter (for CF reader). The 8470p still has that slot and I was able to put the old adapter to use. Now this machine can read my CF without me carrying any external adapter. Quite pleased.
The only shortcoming of this machine is the display. It is only 1366x768. I guess it is because this machine was meant for corporate warriors instead of photographer/videographer like me. But for $252, I can't really complain.
I had just imaged the SSD with all the updates and software loaded. My next step is to swap out the 4<->8 gb DRAM to make it 12gb total DRAM. I am awaiting the DVD caddy and putting the 500gb HHD in it.
All and all, so far, a very happy camper.