For me it depends on the weather. I need more electrolytes when it's warm and I am sweating more. I don't need them for a ride that's less than 4 hours. If it's really hot or it's a long ride I use Endurolytes and salt tablets. Endurolytes don't contain that much salt- I think it's 35mg- so for say a hot 6 hour ride I'd take a couple salt tablets in addition to 6 or so Endurolytes.
The amount of climbing doesn't really affect electrolyte needs, except that when climbing you're more likely to be sweating and thus losing electrolytes. A warm windy day can cause a fair amount of sweating that you won't notice because it's evaporating.
Different people's electrolyte needs vary. Humans supposedly have plenty of electrolytes in reserve but for some reason some people run low after hours of exercise. So some people don't need any supplements while others do.
Did the Endurolytes help? If so, then you may have been low on electrolytes. In my experience if I am low on salt and get some, I perk up noticeably in about 10 minutes. If they didn't help, then you wern't low on electrolytes, you were cramping due to muscle overuse. You fix that by training.