Hand baggage only at an airport I'm reasonably familiar with then around 1 hour. At LHR I start to worry if I'm delayed and I'm starting to look like hitting the 45 minute point, with NCL and PRG I can be relaxed up to 30 mins. LCY I aim for 45 minutes, but know I'll likely be fine even if it passes 30 minutes.
That said sometimes I want to do a bit of lounge hopping. I got to T3 over 5 hours early one time so I could spend a bit of time in each OW and PP lounge I had access to, but that was because a change of plans gave me that spare time so I thought it was worth taking a look at all the options.
If I'm travelling to the airport after work I prefer to head off as soon as I can knowing I can relax in the lounge. Going out for after work drinks can easily lose track of time.