@GreenEyedLad wrote:
Do days spent repairing vacant rental unit count as personal use?
No, provided you are engaged in making the repairs on a substantially full time basis.
Per Section 280A:
The Secretary shall prescribe regulations with respect to the circumstances under which use of the unit for repairs and annual maintenance will not constitute personal use under this paragraph, except that if the taxpayer is engaged in repair and maintenance on a substantially full time basis for any day, such authority shall not allow the Secretary to treat a dwelling unit as being used for personal use by the taxpayer on such day merely because other individuals who are on the premises on such day are not so engaged.