Clear finish = yearly maintenance.
Cedar is naturally durable, so can be left to weather and turn grey, but this isn't to everyone's taste. But this will only require the odd stiff broom brush clean and wash to remove dirt.
You can buy decking oils, they will last 6-18 months, but give a very nice look.
Clear water repellent finishes may last 12-18 months, but are not as decorative, they do however (drum roll) repel water very nicely, which is good in wet n windy Scotland.
translucent stains will (excluding erosion from foot traffic) last several years, but it is the pigmentation that gives them their durability, and so they will change the appearance depending on the level of pigmentation.
I would be very very careful with any clear product with UV inhibitors that claims to last x years, I have seen so many of them exaggerate their life, and then whenever they fail, it's always because you haven't applied it properly etc. If you use any of these products, check the guarantee offered, and follow the instructions to the letter.