Gel Cell Battery

[G.R.]

Roscoe, in a sense you are right and wrong, the caveat being if the deep cycle is discharged much below 12 volts then rapidly re-charged with out a regulated charge cycle they will fail far faster than a normal battery and deep cycles do not like rapid discharges such as that used in starting a cold engine. That is why in the marine world deep cycle batteries are not generally used as a starting battery. Nigel Calder is sort of a marine electrical guru and is highly regarded for his knowledge with 12v systems. Aboard typical cruising sailboats where battery power is your "electrical power grid", he recommends deep cycles for House banks and dedicated non-deep cycle starting batteries.
Deep cycle batteries do/can get "memories" if not properly maintained. But I'll bet you a dollar to a donut that if you take 2 batterys of the same size, one a deep cycle and the other a normal AGM or lead-acid type and run them through the start, draw, charge cycle such as an Automotive engine requires/uses, the deep cycle will fail faster than the other unless you have a charge regulator in the circuit.
After having sailed and lived aboard various boats in the last 25 yrs and 2 years sailing in Mexico I feel I have a more than passing knowledge of DC electrical systems and batteries. Lead-acid batteries do not like slow, deep discharge rates, deep cycles do, but they do not long tolerate rapid discharges for long before failing.

BTW golf cart batterys are normally deep discharged then when in the recharge proccess they are hooked up to a regulated type charger not one putting out anywhere from 50-100 amps continuosly like an automotive alternator puts out.