That really depends what you plan to be doing, since the kind of care you’d need to provide can be very different across different situations. The first-aid kit in my car doesn’t look much like the one I take hiking: I’ve got the former kitted out for major trauma (and for minor issues I might encounter away from home) but I don’t expect to be using it for long- or even medium-term care of any kind, while the latter spends more space on quality-of-life issues but needs to provide support for the time it takes to hike out.
That really depends what you plan to be doing, since the kind of care you’d need to provide can be very different across different situations. The first-aid kit in my car doesn’t look much like the one I take hiking: I’ve got the former kitted out for major trauma (and for minor issues I might encounter away from home) but I don’t expect to be using it for long- or even medium-term care of any kind, while the latter spends more space on quality-of-life issues but needs to provide support for the time it takes to hike out.