How many revolving TL is enough ?

[jetsfan2013]

Over the weekend I visited a friend and his wife, and the topic of homeownership arose. His wife works as an Underwriter at a large lender, and mentioned that together they both had paid off all of their debt, and had zero owed on the 1 credit card that remained open (at one point she shared they had 14, closed all the rest in 2016 after paying off). 

I was under the assumption that many closed accts would negatively impact their scores, but she said because they were all "new" less than 2 years old, there was little impact. Is it wise to have at least 1 revolving tradeline open before applying? If you have none will that hurt? I will not owe any installment loan debt when I apply as car note and student loans will be gone.

[ShanetheMortgageMan]

Revolving trade lines aren't required, however they really help your scores get as high as possible.  I've seen people try to re-establish credit with only installment trade lines and I notice their scores aren't as high as when people re-establish credit with only revolving trade lines and especially if it's a combination of revolving + installment.  So, no they aren't required, but they will help.