Throw away stuff to free up space.
However technically it barely matters.
Most things don't take up that much space.
For some things some spare thought of the potential shock thought of discarding something needed way later.
If society thinks YOU will think its sentimental probably better to just keep it to save yourself burden of replacing yourself. (Photos.) And the stigma.
However it frees up mental clutter.
Which can be pretty great.
The problem of whether you would regret it is a bigger one though...
Mind might be reality. I don't know. There are benefits to total decluttering. But maybe also remembrances from it was there...
Perhaps it is just that in terms of utility, physical items often have one use. Pen for writing, scissors for cutting, clothes for wearing... of course, some stuff like computers are exempt though. However there are some that just won't benefit much due to pragmatism or replaced or redundancy (e.g. already owning/alternative)
So can give or throw or just hide the item.