Most people that do the conversions do so with the idea that the tax bite may be higher when they are retired and time comes for minimum distributions, than the tax bite when they do the conversion. One is speculating on the future which is always unknown.
The biggest unknown of course is ones longevity. If one does not reach the golden years (heaven forbid) a conversion is complicated because now you are not only considering your tax liability but also your heirs tax liability, as to whether it was worthwhile. Another assumption is that the investment will increase once the conversion has been made. That may not be the case where people raided their retirement funds after losing a job or having a family emergency. Just lots of unknowns with Roth conversions.
I am retired and have decided against doing any. My advisors have always recommended to not pay a penny of tax until it is absolutely necessary. So that is the approach we have taken. Our tax savings are in the here and now, and I think that is going to be the best course for us.
