Carry a small hammer with you if you're still driving this with the same starter. LOL
Just sayin....
One loud "clack/click" and then nothing is the starter seizing up. If you try it enough times it may free up and start. If the relay was the issue you would not even hear the "loud click/clack then nothing" symptom. Your starter is near dead and no tapping on it will fix it if it's bad enough or just decides to "give up the ghost" (smoke) due to being seized and super high amps burning it up. I hate being stranded at the least opportune times.