borewell water softener

For mild hardness, yes. A water softener can improve bathing water quality in many homes, but for very hard borewell water, a higher-capacity softener typically works better.

It can help reduce new stains caused by iron particles. A water softener may lower the amount of iron-related residue that leads to fresh brown stains, though old stains may still need manual cleaning.

No. Maintaining a water softener usually just means replacing the cartridge on time, which is typically much cheaper than repeated appliance repairs caused by hard water scaling.