I haven't used an ignition controlled relay to isolate my heated grips, my USB charger, nor my GPS. One reason for that is that I want my GPS powered all the time. Having its power go off with the ignition would mean the GPS would shut down every time I stopped the bike unless I remember to tell it not to. That's a pain on a trip.
You could isolate your accessories using a NO switch either alone, or to a relay. That way for overnight you can flip the switch and prevent any possibility of parasitic drain and a dead battery.
I wouldn't want to leave multiple accessories connected directly to the battery long term, especially if you're going to leave the bike in the rain, or have made your own wiring (unless you have used waterproof connectors and done a really good job, like I have
I've always read that electrical faults are the #1 cause of motorcycle trips being interrupted/stopped. I've also done my own wiring for both my bikes, and I've found that it really isn't that expensive to do wiring the right way, using good waterproof connectors (I use Deutsch), heat shrink up the wazoo instead of electrical tape, and making sure you don't have any exposed metal. You can wire stuff up for pennies, so doing it right is a large percentage more expensive, but in overall cost compared to other mods, doing the wiring right is very cheap, and extremely worth the money.
The front end of my bike is crazy with wiring as I have added a ton of stuff:
1. Relay for my Denali Soundblaster Horn
2. Third wire for new turn signals with a running light (using Yamaha 3-pin connectors that are small enough to fit through the turn signal nut)
3. 3 constantly powered 2-pin Deutsch connectors mounted to a panel under the gauge (through the ignition relay on my fuseblock). They power by cig/USB ports, my voltmeter, and my heated grips.
4. 4 2-pin Deutsch 2-pin connectors. Right now they power 2 add-on LED lights, and I threw 2 more in there because they fit, and I figured I might as well add them while I'm in there...
I know that is pretty excessive, but it has proved very useful so far. The ports are easily accessible without removing any fairing or the apron, and I think the wiring is pretty bulletproof. I am waiting on some new small connectors to replace the couple bullet connectors in the picture, but besides that, the only risk I think is the fact that the relays aren't waterproof, which I think is ok. I wish I had a picture of the before state with a rat's nest of wires, which was not great.