Mark's Guitar Exchange in Chula Vista's Otay Lakes corridor has operated as the city's only full-service guitar shop since 1985, stocking acoustic and electric instruments, amplifiers, strings, and Seymour Duncan pickups from its Unit G storefront at 945 Otay Lakes Road. The store pairs retail sales with in-house repair and private lesson programs, building a combined sales-service-education model that complements the performing-arts instruction at Neisha's Dance & Music Academy in the broader Chula Vista arts community. A dedicated repair bench handles fret leveling, truss-rod adjustments, pickup swaps, and full setup work on both steel-string and nylon-string instruments. The shop's Workshop Series hosts clinics on gear selection, amp settings, and effects-pedal signal chains, feeding into the same live-performance pipeline that puts musicians on stage at On Stage Playhouse in the Third Avenue Village district. Setup technicians calibrate string action to manufacturer specifications using radius gauges, feeler gauges, and strobe tuners to ensure intonation accuracy across all fretboard positions.