I will always recommend setting up your own relay, just because that gives you ownership of your social data just like running a bitcoin node gives you the ability to transact bitcoin whenever you want.
I would also recommend to pay for a couple of relays. Not because they're neccessarily better than a free relay but because paid relays has a higher chance of being sustainable than a free relay (without funding). Ironically, I've been running a free relay since mid-april 2022.
Some paid relays also offer extra stuff such as client-specific paid features (e.g. on https://snort.social), LN addresses, NIP-05 hosted verification, email services, backup services, better spam filtering, etc, so you should see if some offer something better than the other.
I'd also add a couple of free relays. If they cause a lot of spam in your feed (they don't for me), maybe change to a different relay.
If you're going to selfhost a relay, there are many ways to do that depending on your skill level. If you have an umbrel at home, you can set up a relay there. If you have an instance of lnbits running somewhere, you could install a relay there.
If you want to set stuff up yourself, I'd recommend strfry or nostr-rs-relay. Both has some documentation on how to get it set up but you need to know your way around a terminal and web server setup. Another popular relay software is nostream.
And if you selfhost a relay, you'd probably want to limit who can write to it to either just you or a close set of friends or anons you trust to ensure that it's not filled with spam by bad actors. All the relay softwares I listed above has some functionality for filtering events, usually through a separate plugin.
How much time does it take to run a relay? Once it's set up, the maintenance part is just to keep software up to date (which honestly doesn't need to be that often), at least if the relay is just for you or a small group of npubs. If you open the relay to the rest of the world, there might be a bit more maintenance w.r.t fighting spam, ensuring proper performance, disk space, etc.
TL;DR: Run your own relay if you can. If not, find some relays you trust to keep your data and do occational backups of your notes in case all your relays go down.