When I was thinking about using clouds in my private space, the cloud topic had boomed already. Due to the fact I was running a vserver, i simply downloaded ownCloud to my server and gave it a fresh install. I was pretty cool with all the stuff, ownCloud provided when there was a news article (dunno where I found it) about nextCloud. nextCloud was a fork of the ownCloud repository which was forked under the lead of a former developer of ownCloud, because ownCloud got too commercial in his eyes. After testing the new stuff, i decided to install a nextCloud instance and migrate all my data to it.
From the moment I decided to use "cloud services" hosted by myself my life turned out to be easier. I started to store all my contacts in my nextCloud, synced via CardDAV and all my calendars and tasks synced via CalDAV to my mobile device. To sync that stuff i'm using the app DAVdroid which gets that job done properly and is woth every penny. The tasks, which make my life a lot easier, are managed by OpenTasks on my smartphone. Of course, the data that's stored in my cloud is synced via WebDAV with the relying desktop client from nextCloud and the nextCloud app. On my desktop PC I manage my tasks and the calendar via emClient which is also worth buying but offers a free license for private use.
I not only got control of all my data, can easily switch my cell phone or the fact to have a replicated set of data on all of my end devices but also I realized i get more shit done when making use of the OpenTasks app, cause you can simply create tasks for the evening when you approximately sit in front of your home pc and get the notification for the task you need to get done. I wouldn't have used the OpenTasks app when I wouldn't have dealt with how to get my nextCloud data to my phone.