Most cheaper phones suffer battery bloat within a year. I retired from mining when the profit per day dropped from 10c to 1c. At least before it was possible to make a return before the phone cracked itself. Unless you have a supply of free phones from a recycler, I wouldn't bother.
You might also need to account for how much it costs to dispose of a bloated battery. You can't just recycle them as most places won't take them. If you put it in your council bin they will know which bin it came from if the truck catches fire as there are cameras now.