Speed is very important. The higher the gear ratio, the larger the spool, the faster the retrieve. This makes it easier to get gear in and keep a tight line while backing down when fish moves towards you.
Power is the effort taken to wind the handle against the pressure of the line. The higher the gear gear ratio, the harder it is to wind the handle. you will realise the importance of power when you clear rods after a strike, when having to gain line under load and when enjoying an extended battle.
To change speed and power most brands of reels have two speeds like the Omoto GTR and Omoto Poseidon reels. Changing speed or , more precisely, changing gears, does not have anything to do with drag settings. The reel will be in high speed most of the time. Low gear is used when you want to turn a fish by putting maximum pressure on by keeping the rod high and using very slow, short strokes, gaining only a few inches at a time. If a fish is deep and you cannot wind against the stretched line, low speed will enable you to do so. During a long fight, a tired angler can relax by dropping to low gear and winding steadily without necessarily pumping the rod. This gives the angler time to have a rest while keeping pressure on the fish and gaining line. As soon as you can gain line easily on low speed, resume high speed.
Drags, also known as clutches, must be smooth. The preference is for lever drag reels such as Omoto GTR and Omoto Poseidon reels. Lever drags allow you to set a known drag in a known position on their drag lever arc. They often have strike buttons and markings for your preferred settings. This type of drag allows you to fight by increasing or decreasing pressures as fight progresses, while always knowing where your predefined setting is.
To check the drag set your drag to one third the breaking strain of the main line. Get someone to pull the line smoothly. If the tip jerks service the drag. Clean your drags with white spirits and let them dry before reassembling them. Do not over grease the gears, too much grease clogs the gears and may restrict your free spool.