I would also add the since all 3 reports could have different, sometimes import differences, you must check all 3 reports at least once a year.
After having been declined repeatedly the past two years for everything from department store cards, auto financing, visa, mastercard and even secured cards... I have to say that although they all matter.... But Experian matters the most.
It depends on the creditor. Some pull all three, some pull two and a few might even only pull one.. But in my experience, they ALL primarily pull from Experian. (Go figure that EX has my lowest score.)
My hard inquiry distribution for the last 12 months is as follows:
My advice: Work on all 3 CBs but focus on EX.
EX: 566 PLUS/FAKO
EQ: 646 FICO
TU: 597 FICO
Mine pulls in the last 23 months have been:
EX 1 Amex
EQ 3 CU twice and Auto Loan (Toyota)
TU 1 Lowes (GEMB)