Electrical permits are cheap, and the reason to get one has little to do with the fee.
What generally requires one
New circuits.
Panel replacement or a service upgrade.
Anything involving the service equipment or the meter.
Substantial alteration — a kitchen or bathroom renovation, an addition, a garage conversion.
Adding equipment with a dedicated circuit — an EV charger, a hot tub, a heat pump.
What generally does not
Like-for-like replacement of a device — a switch, a receptacle, a light fixture — in most jurisdictions.
Replacing a breaker with an identical one.
Requirements vary and the local building department will say. It is a phone call.
What the inspection actually catches
Not the things a homeowner would notice. The things behind the drywall:
Conductor size against breaker size.
Box fill, which limits how many conductors may be in an enclosure.
Grounding and bonding — the electrode system, the subpanel separation, the CSST bond.
AFCI and GFCI protection where required.
Cable support and protection — staples at the right intervals, nail plates where cable passes through framing within reach of a fastener.
Working clearance at the panel.
Connections, torqued and made correctly.
Every one of these is invisible once the walls close, and every one of them is a fault that shows up years later as heat, an arc, or a shock.
The rough-in inspection
On any work involving open walls, there are two inspections: rough-in, before the insulation and drywall, and final, after the devices are in.
The rough-in is the valuable one. A missed nail plate found then costs nothing; found after the tiling it costs a wall.
This is why work done without a permit is done without the only check that happens at the right moment.
Unpermitted work follows the house
At sale, disclosure requirements in most places cover known unpermitted work.
A buyer's inspector who identifies obviously newer wiring with no permit history will raise it, and the usual outcomes are a price concession, a demand to permit it retroactively, or a demand to have it opened up and inspected.
Retroactive permitting exists and it is more expensive and more invasive than doing it at the time, because the walls have to be opened for the inspector to see anything.
Insurers may also decline a claim traced to unpermitted electrical work, which is the version of this problem with the largest number attached.
Homeowner permits
Most jurisdictions allow a homeowner to pull a permit for work on their own primary residence, and the same inspections apply.
That is a legitimate path for someone competent, and the inspection is a benefit rather than an obstacle — it is an experienced person checking the work for a small fee.
Rental and commercial property generally requires a licensed contractor.
The cost
An electrical permit for residential work is typically a small fixed fee plus a per-circuit or valuation-based component. Against the cost of the work it is minor, and against the cost of any of the outcomes above it is negligible.
A contractor who proposes to skip it is proposing that the homeowner absorb the disclosure problem and the risk, in exchange for the fee and the scheduling delay. That is not a trade worth making.
The utility connection depends on it
On a service upgrade the utility will not reconnect until the inspection has passed, and the inspection does not happen without a permit.
That makes the permit unavoidable on that particular job, and it is worth knowing because it is the one case where skipping it is not an option a contractor can offer, whatever they say beforehand.
Timing
Inspections are usually scheduled a day or two out, and in busy periods longer.
On work where the walls are waiting to be closed or the power is off, that scheduling is part of the project timeline rather than an afterthought, and it is worth asking a contractor how they plan around it.