HELP - Bathtub Replace or Repair?

[Layne T.]

I've got a 3/2 rental about 20 years old, where each bathtub has a crack (see above) on the base of the tub. Questions for those who have gone through this:

1 - Is this deep enough where I have to worry about potential water damage to floorboards already? 

2 - Is a $500 re-glazing job worth it vs. a full $2k replacement job? 

I've been reading how even a resurfacing job can crack over the crack with pressure over time, and they are usually only coming with a one year warranty for crack repair. Thoughts?

Thank you!