I did it about 20 years ago.
I was informed before I started it would be around 2 weeks.
All jurors were held in a 'green room' type room. A court official came through and called my name.
We were asked in court if any of the main participants had any reasons or objections to any of us (eg. if we were known to any of them) We were sworn in.
First case - it was a weird drug dealing offence. Very strange it came to court as there wasn't a huge amount of evidence. That was a hung jury and the jury was dismissed. This took about 3 days.
I was sent back to the 'green room'. Next day my name called again. New jury, new case. This time it was attempted murder. It was horrible. I was quite blasé after the first one.
The reminder of my jury time was on this case. We returned a guilty verdict 10 - 2,majority.
Looking back I enjoyed the experience. It's true a huge amount of it was slow paced and dull. It's hard not to drift off and loose concentration. But you must.
I was self employed at the time. I submitted a few invoices as proof of earnings and they provided me with 'expenses' I think it was about £300 for the 2 weeks (loss of earnings etc)