I find the change from having a family not very large, say 2x food and perhaps to be very generous +1k clothing. The chief difference is the desire to live in a own space instead of having roommates, which are hard to find with a family.
Suppose you live in Cambridge, MA and eat all organic food; rent with roommates and utilities costs perhaps 800/mo, subway costs perhaps 100/mo, food costs 300/mo, clothing is perhaps 100/mo, health insurance perhaps 1k/mo. This adds up to 1300/mo, 28k/year. Throw in a very luxurious 5k/year in travel, 4k/year in restaurants and hobbies, and your 100k salary / 67k takehome pay supports you saving 30k/year (more if you use tax advantaged accounts).
Consider a family of four in such a case. Taxes run about 21k/year instead of 33k/year, so takehome is 79k. A 1br in Cambridge runs about 2k/mo, maybe 2.5k/mo for luxury. Subway is 150/mo, food costs 700/mo, clothing of say 200/mo, healthcare is perhaps 1.5k/mo; these run 5k/mo in total, 60k/year. Throw in 5k for travel, rental cars, and hobbies, and you're still saving 15k/year for emergencies.
This seems like a very luxurious life, as someone who's lived it; expensive, and I found it slightly more luxurious than makes me happy. So yes, families affect saving rate, but also provide perpetual free entertainment.
Childcare makes a huge difference. Most people with kids either have to sacrifice a huge chunk of their income or a huge chunk of their income-earning potential.
Suppose you live in Cambridge, MA and eat all organic food; rent with roommates and utilities costs perhaps 800/mo, subway costs perhaps 100/mo, food costs 300/mo, clothing is perhaps 100/mo, health insurance perhaps 1k/mo. This adds up to 1300/mo, 28k/year. Throw in a very luxurious 5k/year in travel, 4k/year in restaurants and hobbies, and your 100k salary / 67k takehome pay supports you saving 30k/year (more if you use tax advantaged accounts).
Consider a family of four in such a case. Taxes run about 21k/year instead of 33k/year, so takehome is 79k. A 1br in Cambridge runs about 2k/mo, maybe 2.5k/mo for luxury. Subway is 150/mo, food costs 700/mo, clothing of say 200/mo, healthcare is perhaps 1.5k/mo; these run 5k/mo in total, 60k/year. Throw in 5k for travel, rental cars, and hobbies, and you're still saving 15k/year for emergencies.
This seems like a very luxurious life, as someone who's lived it; expensive, and I found it slightly more luxurious than makes me happy. So yes, families affect saving rate, but also provide perpetual free entertainment.