STRINGS
New strings can breathe new life into your bass. Much of the thump and pop you expect from your bass starts right there. For strings to stay in tune, they should be changed regularly. Strings that have lost their integrity (worn where pressed against the fret) or have become oxidized, rusty and dirty will not return to pitch properly. To check if your strings need changing, run a finger underneath the string and feel for dirt, rust or flat spots. If you find any of these, you should change your strings.
Fender offers a variety of bass strings—smooth, vintage-sounding pure-nickel Original Bass 7150s; Super Bass 7250s; bright, snappy Stainless Steel 7350s and others. They are available in long, medium and short scales; taper-wound; and top-loading or string-through-body types
Because of the amount of tension on the neck, it’s advisable to replace and tune each new string before removing the next string. After the whole set is changed and tuned, stretch your strings properly by holding them at the first fret and hooking your fingers under each string (one at a time) and then tugging lightly, moving your hand from the bridge to the neck. Re-tune and repeat several times.