Why is there a limit, what is the typical limit, what is the limit dependent on, and what harm will it do if the limit is ignored?
What lamp and ballast you mean?
Probe start (MV, MH): Limited by wiring resistance drop only (should not exceed 10..20V), as regular power wiring (so no practical limit).
Pulse start (MH, HPS): Limit imposed by wiring maximum capacitance. As these rely to short pulse generated by the ignitor. As the pulse is short, too high capacitance might prevent it from reaching high enough voltage. So longer cable, having higher capacitance, need more energetic pulse, for shorter wiring lower energy (so cheaper) ignitor suffices. So ignitors (so ballasts) are rated for maximum capacitance they are able to drive: "Short range" (regular) are limited by ~200pF (what mean about 4..6feet/1.5..2m), "long range" are able to drive 2..10nF, what mean 40..200foot/13..70m of cable, depend on type. Superimposed style ignitor has limited length for the connection to the lamp, connection to the ballast has no capacitance limit, so on space or weight constrained fixtures only the small ignitor should be close to lamp, the rest of ballast might be remote.
Otherwise the limit for MV apply as well.
Fluorescents:
Mais (low) frequency "magnetic":
Preheat: No technical limits, but for remote ballasted fixtures is practical to keep starter close to lamp (reduce wiring)
Instant start: No technical limit
RS: Filament circuits are limited in resistance, as they operate on low voltage (so even small drop cause large consequences)
High frequency (electronic): All should have wiring as short as possible, as the long wiring would serve as an antenna radiating the HF current, so cause electromagnetic compatibility issues. Beside of this too high capacitances and/or inductances associated with long wiring could interfere with ballast functionality (e.g. reduce heating current for voltage mode preheat, inhibit protection circuits properly detect failure modes, disturbing current regulation - mainly on dimming ballasts)
