A tip that I didn't realize until I'd been flying IFR for a while -
You can file IFR off any fix, not just an airport. So your flight plan can begin at a VOR, or anywhere else, and you pick it up from the nearest ARTCC frequency when you get there. Some possible use cases:
Leaving Oshkosh this is recommended as you can't pick up IFR at the field. They give several recommended fixes to file from depending on your direction of travel. I should have done that this year and didn't, ended up having to call and get a pop-up clearance to get home when there were clouds where they weren't forecasted to be.
Leaving a busy airport in VFR conditions, but headed into IFR conditions later in the flight. You can skip the "hold for release" delays and mandatory obstacle departure procedures you may not want to fly in clear weather. If you haven't experienced these, you will if you ever fly in Bravos, especially on the east coast, or in the mountains. Controllers seem to like it and will often let you skip the line and depart quickly VFR.
Taking off somewhere where you want to do a scenic tour or circle around a bit, then head to your destination.
Now with Starlink you can even file mid-flight off a fix somewhere along your route and pick it up when you get there.
To answer the main question, I don't do much taking off in near-IMC conditions expecting to get a clearance. I'd much rather call ATC on my cell phone if I can't reach them on the radio and sit tight on the ground until cleared. Not much fun bouncing around below the clouds, staring at the ground not very far below you, looking for towers, and waiting for them to give you a clearance, while hoping no traffic comes along that you're supposed to see and avoid.