What do you mean by trip?
Are you talking close to home or away on an extended trip?
If extended are you isolated or near towns and services?
For us tools and spares vary according to what we are doing.
We do some isolated stuff and take heaps, we have used b all of it I might add. But its better to look at it than look for it.
If doing a weekend trip we dont take much, only cause we are close to home.