How Do I Make My Stuff Stop Dissapearing?

If i make something then later it is returned to me by "parcel auto-return" yet i see plenty of people's stuff thats been there for weeks. how do i make my stuff stay?

Don't build or rezz things on other people's parcels. Unless you own a parcel yourself, you have no guarentee that the items won't be returned. On group owned land with auto-return, joining the group and setting (not deeding) the objects you rezz to said group is usually enough to avoid having your stuff auto-returned.

Do you own the parcel you're building on? Because "other people stuff that been there for weeks" might be ones of the actual single/group owner responsible for setting the auto-return option at the first place...

Sounds like the owner of the parcel has auto return for objects placed on the parcel that are not allowed by everyone. It's most likely a group thing..........meaning if you are not in the group and the owner has auto return for non group items the items will be returned.
If you are part of the group and they still are being returned then you may have to set the items to the group. The easiest way I know is to wear the group tag when you set or make your item on the parcel. But you can also set it to a group in edit. But it sounds like you must be in the group regardless.

Just a guess............but it sure sounds like that is the case.