Is it a good idea to roam as a support?

I know the title sounds stupid for those experienced at the game but I'm starting to feel like it is not worth it. I don't just roam at random times, I try to find times where I feel it is safe to roam. Examples like the enemy bot laners are gone due to them being dead, recalling or moving somewhere else, our team has a huge advantage so the enemy obviously will not fight, allies farming near our own turrets, etc.

However even when I feel like I picked good times to roam I have problems like: not being near the farm and thus I fall greatly behind in xp and thus become much lower level than the rest of the players, assassins coming out of nowhere and blowing up carries, not being around minions so I'm not making as much money through relic shield and ancient coin quests.

Right now if my ADC is in a good spot, I leave him for about 20 seconds to place some far away wards so we have time to react to danger. So my question is should I be gone longer to make deeper wards and risk falling behind in level, stay with ADC more often to stay caught up in xp, or try to gank another lane?