Depends really. As long it has downloads or I login in my account there, they will never disappear (unless the site changes its policy):
How long does Mediafire store files?
For MediaPro subscribers, your uploaded files will be stored forever as long as your Pro account is active. For free accounts, there is currently no time limit on how long uploaded files will be stored as long as you access your account (i.e. login to your account) or your files are being accessed (i.e. downloaded). Every account is different and different accounts may become inactive at different times.
Users receive at least 4 notification emails that files are pending deletion before any deletion actually occurs. Logging into your account is sufficient to prevent deletions.
MediaFire is the best free file hosting atm (hence using it).
Furthermore, I uploaded to ModDB as well, and I am sure some people like medor, Flay and others will create further mirrors for it, so worst case scenario the mod can still be found somewhere.
Before I uploaded only to ModDB since they upload to GameFront and get stored forever, but then GameFront stabbed a lot of people in the back by removing their service from certain countries all of a sudden, so I had to host somehow for full global access.
But thanks for the heads up anyway.