Please help me understand the Safe Harbor Election for Small Taxpayers (SHST) and the De Minimis Safe Harbor Election (DMSH).

 Safe Harbor Election for Small Taxpayers (SHST) 

  De Minimis Safe Harbor Election (DMSH)

I know the threshold for SHST is $10,000 for rental improvements and $2,500 for a single item under DMSH.

1. Can I use both SHST and DMSH?
2. Do regular rental repairs, such as a leaky faucet replacement, count toward the SHST threshold or not?

Is the example below correct?

• HVAC Replacement -improvment($9,500) → Can be expensed under SHST.
• Refrigerator Replacement ($2,000) → Can be expensed separately under DMSH since it's under $2,500 per item.
• Regular Rental Repairs ($3,000) → Normally deductible as an expense (repairs are not considered capital improvements).