Unless you have a circuit designed for leaky transistors…
Healthy debate here.
Leaky transistors will cause bias to shift due to temperature but also simply playing them in a room temperature room. I've seen my bias drift even with low leakage transistors and a reasonable amount of playing time in my temperature controlled playing area.
In this day and age, and in my opinion of course, that's a design flaw. We can design that irregularity out of the equation yet still call upon it when we want.
Which does not detract from some of the design ingenuity of those old circuits. They used leakage to provide gating characteristics that eliminated, to a certain degree, the godawful noise issues in some of those fuzz circuits.
Short story long, leakage is not desirable. It's a flaw to be worked around. Yes, vintage circuits, in stock form, will bias correctly with leaky transistors. They will also exhibit major bias shift under even relatively normal circumstances. Variable and/or revised fixed bias resistors and low leakage transistors are much easier to get consistent results out of.
With that said, transistors also exhibit certain frequency characteristics between devices. So, sometimes the overall tone you desire comes from a leaky PNP transistors. It is what it is. I like the low leakage 2N169 but am moving mostly toward NOS Silicons because they seem to get me the tone I like over Germanium. I ordered a gang of old Silicon transistors from Small Bear in my last order.
Just my $0.02. Take that with a HUGE grain of salt!
