The right answer is not general, it is specific to the people using that bathroom. A household with small children uses a tub daily and would feel its absence immediately. A household of adults who have not filled the tub in years is stepping over a tub wall twice a day for no reason at all. Somewhere between those is a house where one person wants a soak and everyone else wants a proper shower.
Which bathroom it is matters just as much. A hall bath serving kids and guests is the natural place to keep a tub, since that is where a tub gets used and where a future buyer expects to find one. The primary bath is where a shower conversion usually makes the most sense, because it serves two adults who almost certainly shower and who benefit most from the easier entry.
People imagine a conversion as removing one object and setting down another. The plumbing does not work that way. A tub drains at one end of the unit, through a fitting at the base of a vessel that holds water. A shower drains from a point in the middle of a floor that has to slope toward it from every direction. Those two drains sit in different places and at different elevations, and the floor is what stands between them.
So the floor gets opened. The drain is cut in, relocated, and set at the height the new pan requires, with the fall and venting still working correctly afterward. That is the step that turns a fixture change into a real remodel, and it is also the step that lets everything else be done right, since with the floor open the framing and subfloor under the old tub finally get looked at.
The obvious loss is the ability to take a bath, which some people miss more than they expect and others never think about again. Less obvious is what a tub does for a household that has not needed it yet: washing a dog, soaking something large, bathing a small child, or handling a family member who cannot stand safely in a shower. A tub is an awkward answer to several of those, but it is an answer.
There is also the question of putting one back. A tub returned to a bathroom that has been converted means opening the floor again, moving the drain again, and rebuilding the surround. It is not impossible and it is not exotic, but it is a full project rather than a change of mind. That asymmetry is a good reason to sit with the decision before demo instead of during it.
The simplest conversions stay inside the footprint the tub occupied. A standard alcove is a well-proportioned shower, the framing stays untouched, and the drain moves a short distance. Once you widen the opening, push into a closet, or take space from an adjacent room, you have added framing, possible electrical, and drywall work well beyond the bathroom, and the project changes character entirely.
Then there is the entry. A curb is straightforward, contains water reliably, and is what most conversions get. A curbless entry is the better long-term choice for accessibility but requires the shower floor recessed into the framing, which depends on your joists and what is underneath the room. Glass comes last in every case, measured to the finished tile, and it is worth deciding early whether you want a single panel or a full enclosure with a door.
If the tub in question is the only one in the house, slow down. This is not about a resale figure, and anyone quoting you one is guessing. It is about the range of people who might live in that house next, and about the fact that a home with no tub anywhere is a narrower proposition than one with a tub in a hall bath. If you plan to be there a long time, weigh it against your own daily use and decide accordingly.
When there is a second tub elsewhere in the house, most of that concern disappears and the decision becomes practical. Convert the shower you actually use, keep the tub where it makes sense, and get the accessibility benefit in the room where you want it. That combination is the most common outcome we see, and it is usually the one people are happiest with afterward.
Not properly. A shower pan slopes from all directions to a drain in the field of the floor, while a tub drains at one end through the tub itself. Setting a shower over an unmoved tub drain compromises the slope, the pan, or both. Assume the floor gets opened, and treat any quote that says otherwise with suspicion.
Usually the hall or secondary bath. That is where children get bathed, where guests expect one, and where a future buyer looks for it. The primary bath is where a shower conversion tends to pay off in daily use, since it serves adults who shower and benefit from a lower or absent threshold every single day.
It depends on how it is built rather than on the category. A tiled shower has more grout lines than a tub surround, and small-format tile has considerably more. A larger tile, a well-detailed pan, and glass that gets squeegeed stay easier. The bigger factor is ventilation, since a room that dries out quickly stays cleaner than one that does not.
Which bathroom it is, and whether anything needs to move. That is enough to begin.
