Depends on what you want to get. There are hotel cards where a certain spend gets you status (ie $30k = Gold SPG). There are airline cards where a certain spend gets you status or close (ie $30k = 15k DL MQMs).

Then there are some cards where a certain level of spend gives bonus "multi-use" points.

You need to decide what you want and go from there.

Plus I echo the previous comment; I have a very solid income and great credit history and can count on 1 finger the number of credit cards I got which had above a $20k limit when I initially signed up - and that was with my investment bank who had my assets in their accounts.