Figures I've seen indicate about 10 hours as a base then add 1 hour per year of age from about 21 upwards.
ie if you're 40 its 10 + 19 = 29 hrs
Us poor old ****ers just don't learn so fast - and forget even quicker
. Of course, if you only fly every 3 weeks or have a rubbish instructor or bad weather or ..........