I think you should.If you don't then component behind bad cap will try
to pull electric power it was designed to operate with and in that process
something will get hot and in the end burn out.Caps are cheap to get while
Amiga custom chips are hard to find.It takes long time for cap to dry/leak
on average Amiga and if you worry about that you can always replace cap
with better one that will last longer (for example 1000 microF 10 V cap can
be replaced by 1000 microF 16 V cap that will get less hot and last longer.
You don't have to replace all caps , there is a small piece of kit to test capacity but you still need to take it out of motherboard to do that.
I would advise 60-90 % ethanol alcohol to clean motherboard , anything that
can eat away at contacts would be disaster.Also , PSU should be kept in
good shape too.It can cause damage to caps.
And SMD (ceramic looking) caps can be replaced with regular ones if you are handy enough.
