Depending on the year of vehical you may have to buy a fuel line wrench to release the fuel lines.
For fuel injection, don't forget to relieve the pressure in the fuel line first!!
Not a bad idea to also shut off the fuel pump at the safety switch located behind the kick panel on the passenger side of truck.
Where ever you purchse the fuel filter, ask them if your make & model requires a special wrench for releasing your fuel lines.
IMO, I believe this is one reason why so many never replace their fuel filters. So many people I speak with say they can never get the fuel lines to release.
the right tool & patience allows it to come off easy.
Note: never cut & replace fuel line with regular fuel lines if you have fuel injection. These fuel lines can only be replaced with fuel lines designed for fuel injection because of the pressure.
Replacement fuel lines can now be purchased at most auto parts stores.