personally, I solder EVERYTHING... the only thing that won't be soldered is if a wire is terminated in a junction type block (fuse holder, distro blk... etc..)
you'd be surprised how few pro's do this.... I've argued with plenty who will try to tell you it's not necissary.... as a matter of fact, I'd say that almost no one really solders everything as far as install shops go.... but the reason is to be competitive pricewise & to be able to be productive time wise... you see guys advertizing alarms installed complete for $249... guy down the block says $229.... then the guy around the corner does a $199 special..... most customers are totally stupid & actually shop ON PRICE!!!! so that's what you get....
for me to PROPERLY install a remote start alarm I'll take anywhere from 6 hours to double that & more depending on the vehicle..... I don't do my installs for the public anymore, but I did an escalade for a good customer recently, & the new cars are a ton of work, with special interfaces, etc... it cost this guy like $800 in labor alone to do it right!!
most ignorant consumers are the cause of the shoddy work!!!! I have customers/friends ask me all the time... there looking to spend a few hundred to install a remote start!!!!! I naturally tell them of the mistake they are making, & that a proper install will START in the $6-700 range easily... but BS... the next thing yah know, "oh, I got it istalled for $350 from xyz whatever"....
shoddy workmanship is caused by ignorant consumers that are driven on price & price alone...
