IME, it depends on the song, the standards of the project, and the individual's sense of accomplishment.
And it's important to note that in a cover band situation, "right" versus "wrong" or "bad mediocre good better best" are purely subjective.
I can say that as a covers bass player for several decades I have never done less than important phrases that are signature or supportive to the overall arrangement and maybe a little additive or subtractive non-distracting embellishing. That has kept me and my rhythm sections working a lot and in-demand. BL's know they can count on me, and some BL's can have sensitive ears and be very picky. I try to give them no reason to give me the hairy eyeball, and I want the call-back.
Most often, if I really like the line, the way it was composed and how vital it is to the arrangement and recognition of an established "hit" or crowd-pleaser, I go for as close to note-for-note as possible. I figure that original bass player wrote and/or played a line that helped sell millions of copies of the recording, concert tickets, tee shirts, and maybe I have something to learn from him or her rather than imposing my own not-so-clever "interpretation."
Also important to note that I do not find myself in projects where a complete re-working of the most popular arrangement is the project standard. The bands I play in, no one has those kind of creative or arrangement chops, and even if they did it would probably be wasted because we have a target mainstream dance party audience who wants to hear their favorite songs "like the record."
I have what I consider some very good reasons for being perhaps on the more faithful, detail-oriented end of the spectrum. If the line was recorded simple and that supports the song, and if it ain't broke, why fix it? That's an indulgence I rarely take. Also, I usually learn a lot about music, technique, fingerings, etc. from a well-composed bass line.
The "practice like your life depends on it" is kind of amusing in wee bit snarky way. At first, yeah it takes considerable effort. But in a short while your ear improves, your intuitive knowledge and understanding of the fingerboard improves, you get better with different techniques like pick, fingerstyle, slap, and pretty soon you're learning even complex lines in short order and playing them with confidence, consistency, and a command over your instrument, hardly like your life depends on it.