You can do it as full time and participate in translation, signature and youtube bounties which have low competition with high rewards but you have to wait to get your rewards as bounties normally distribute their coins after their ICO over. No one knows, which of your coin change your life. I start it as part-time but now growing my work.
Yes, some of my friends have spent full-time for crypto. They do a lot of bounty campaigns and they also spend some time to research about the projects to investing. It takes them a lot of time, maybe 7 - 8 hours per day and all days of weeks.