The new threshold is 60 percent of AGI for cash contributions held for over a year, and 30 percent of AGI for non-cash assets.
Hope this helps
Yes. If your donations exceed a certain percentage of your income, the deduction will be limited and the unused portion will carry over to the next tax year, for up to 5 years.
Most charities are "50% organizations" which means you can deduct an amount up to 50% of your income (except the limit is currently 60%, even though they are still labeled "50% organizations.") Some organizations are 20% or 30% organizations.
See here for more,
https://www.irs.gov/pub/irs-pdf/p526.pdf
To give an extreme example, if you found a painting in your attic appraised at $1 million and you donate it to a museum, but your income is $100,000 per year, you can only deduct $50,000 as a charitable deduction, and the unused part carries forward for up to 5 years.