Shrink DB bring in cost. After it is shrunk, if no maintenance steps were taken, such as re-indexing DB and archiving data, the DB will grow back to its size. What we see it did not payoff well is, shrink would not respect "well-formed" of DB structure and usually bring in performance impact due to fragmentation after shrink.

Each DB physical disk size can be viewed into an actual data size and and available free space size. Reclaiming available free space that is allocated is not a good practice.

Index fragmentation on large tables would waste some space and you need this fixed up. More appropriately, you need to identify what are the unused index and what are the big index. Unused index may subject to dropping, large index will need close look on how it is used and rework. Typically, any big includes?

Always good to add in more disk space. Shrink is not an option, unless you know what you are doing.