1 Small residential projects tend to cost more per square foot and may be subject to a minimum charge of $500-$1,000 or more. 2  Resurfacing an average 500-square-foot concrete driveway typically costs $2,000-$5,000. ThisOldHouse.com estimates it took two people five hours and six bags ($150-$180) of material to resurface a 9'x27' driveway and a 3'x18' walkway (about 300 square feet). 2  Renting a pressure washer to clean the existing concrete before resurfacing can add $40-$75 to the total DIY costs.
At what point you declare someone mentally mature is hard to define but given that wisdom from life experience would be a good indicator of maturity then the age of someone would imply more life experience. It depends if they have learnt from it I guess.
In yet others, adulthood is attained through trials and tests, and therefore may happen at different ages for different people. Generally, in Western society, we consider age 18 to be the end of adolescence. It approximately overlaps with the end of puberty and the start of legal majority.