On a simple song, it's easy to play it note-for-note if you want to, I know. But on lots of other songs, the bass line is not all that simple. Tabs can be inaccurate or nonexistent, and/or it can be hard to hear all the notes distinctly on a recording. Is close enough, close enough? Take a little artistic license and maybe add a riff or two of your own? Perhaps even simplify it a bit. Or keep working on it until it's nailed note-for-note? I don't think the audience will be able to tell the difference either way, unless the audience is filled with anal retentive musicians. I'm currently working on "Listen To The Music" by the Doobie Bros. Learning this bass line note-for-note would take time. I could probably do it, with more work. But the somewhat simplified version I played last night seemed to satisfy my bandmates just fine.