Sanity check: what’s a comfortable monthly cash buffer for big-city homeowners?

Hi — looking for feedback from homeowners, especially those in bigger cities.

BACKGROUND

• We currently rent and are waiting for a specific house to be listed (in Chicago)
• The owner plans to sell within the next year, so we paused our search since this would be our ideal home.
• Based on comps, we estimate a purchase price of $600k–$650k.

INCOME

• Me: ~$165k/year (includes a $25k–$30k year-end bonus)

• I contribute >6% to 401(k)

• Net Pay (Jan–Nov): $7,025/month

• Net Pay (December)(bonus month): ~$24,000

• Husband: $100k/year

• Contributes significantly to 401(k)

• Net Pay: ~$4,000/month

COMBINED NET INCOME

• Jan–Nov: ~$11,025/month
• December: ~$28,000

SAVINGS APPROACH

• Jan–Nov: We contribute $3,700/month to savings and other investments.
• December, we keep only ~$1,000 of my bonus as additional discretionary cash. The remainder of the bonus goes directly to savings/investments.

HOME PURCHASE ASSUMPTIONS

• Purchase price: $600k–$650k
• Down payment: $130k
• Property taxes: ~$10k/year
• Estimated monthly mortgage: ~$3,800 at $600k , ~$4,100 at $650k
• No other debt

MONTHLY CASH AFTER MORTGAGE + SAVINGS

• January–November Net income: ~$11,025 Savings/Other Investments: $3,700 Mortgage: $3,800–$4,100 Remaining cash: ~$3,225–$3,525/month

• December Remaining cash is roughly the same as a normal month plus ~$1,000.

ADDITIONAL CONTEXT

• No kids currently, but planning for a child within ~2 years.

QUESTIONS

• For homeowners in bigger cities, would our remaining monthly cash be tight for all other expenses?
• If so, what is a comfortable target range for remaining monthly cash? Especially with one kid, as we are planning to expand our family soon

*I’m asking to understand whether — and by how much — our remaining cash may fall short so I can personally decide whether to adjust retirement or other savings/investment contributions or focus on a lower purchase price.