as far as I can see... pills have changed very little in average quality.
generally, it'll take 3 to get me going properly, taken over a couple of hours.
sometimes less... sometimes more... but on average, 3.
I started to take pills with regularity (more than a couple of times a year) in abour '93 and from what I remember, it's always been like this. Occasionally a pill will come along that's so good, 1 - 1.5 will do the job nicely... points on case... the original doves (little fat ones) in '93 - '94 snowballs in '99, speckled mitsis in '00, hearts this year. But averaged across 10 years or so, they seem to have remained roughly the same.
I leave a few months (3 - 4) between taking pills... any less seems to have a deleterious effect on my tolerance.