Although the traditional method of bit-height adjustment involved having a pair of pins on the router motor that tracked in spiral grooves in the base, so you'd loosen the lock nut on the base, and then turn/spin the router motor, some newer designs use other methods, I believe. (All of my routers use the spin design.)
There are also various designs for router lifts, some "after-market" and some original equipment.
My Rockler table uses an insert plate, to which the router is mounted (after removing the stock base). The plate also has 1/4-20 holes on either side of the plate. So, for me, it's easier and quicker to thread in a couple of 1/4-20 bolts and remove the router/plate assembly to the top of the table. Then, everything is in the light, so I can better see to change bits, make height adjustments, etc.
Plus, the two 1/4-20 bolts are a lot cheaper than the after-market lifts.