Should I get a 18/25 tube or a 25/32 tube? I have a 25mm size tyre and I'm ordering some inner tubes on the net.

So far, I seem to have a choice between either the 18/25 range or the 25/32 range.

Both would fit but would one size be better than another?

Would the 25/32 tube heavier to accommodate the 32mm tyres and would the 18/25 size tube would be easier to puncture because it's at the maximum stretch?

Or would this be largely negligible?
It doesn't matter.

The difference in weight is practically non-existent, and puncture resistance is a property of the tire.

You may be able to pack an 18/25 in your spare parts kit a little easier than the 25/32, but that still isn't much of a big difference.

Just get whichever is cheaper.