Can there be anything finer than the sound of your premium quality instrument with a fresh set of strings, stretched and tuned? I don't sit and play often, I usually play when I'm getting ready to track. I've been playing for a few weeks (acoustic 6) getting ready to track. I put new strings on yesterday (Elixer Nano lights) It makes it sound so good having "fresh" strings... Haven't tracked yet, practicing the fretless part. Will track the bass and drums 1st, then the guitars. Good times though :-) Before I track the fretless, I'm replacing the strings on it too (flat wound).
 
New strings... The harmonics are in tune while the open strings are in tune? This is one of life's simple pleasures. Replace your strings! Clean your fretboard!

La Bella flats on my 4003 right now. ;-). I may try TI's next time, I here there is something magical about TI's on a Rick, if your into flats.

I too use Elixer Nano lights except I don't like the strings brand new - they squeek too much.  I like 'em about a day old.
 

I've been meaning to try those new Ernie Ball Aluminum phosphor strings on the Larrivee .

On the fretless I run D'Addario Warm Mellow Flat Wounds (Medium Gauge). The A fore mentioned Elixer's on the acoustic 6 and on the 12. And I agree, a few days old... So I put them on yesterday? I haven't played it yet ;-) 
 
On the fretted bass? (Alembic) It has to be Rotosound...

Restring your guitars "NOW!" :-) It's cheaper than buying a new guitar/bass? But it makes it feel and sound like a new guitar/bass? DO IT!

It adds up though... 20 bux (give or take) for the 6?
 
20 bux give or take for the 12?
 
The bass costs, to re-string it...
 
Then do you want to play mando? Dobro? If so, they need new strings to record. 
 
It adds up? Still, I require it... It is mandated...

Can there be anything finer than the sound of your premium quality instrument with a fresh set of strings, stretched and tuned? 

 
Yes - a nice bass with nice old strings. 

Wasn't it Jamerson that never changed strings? :-)

Yeah, that's supposedly the story.