First, the ones that are only a cleaning
Overflowing in a storm, visible leaves and grit in the trough, a downspout that trickles while the gutter above it brims. That is a full or clogged gutter, not a failed one. A proper cleaning (hand scoop, flush every downspout) solves it, and you should not let anyone talk a clog into a catastrophe. Run the free checker if you are not sure.
Then, the ones that are a repair
A single sagging run, one leaking seam, a downspout that blew off, or a stretch that overflows in the same spot even when clean. Those are repairs: re-hanging, re-sloping, or a seam sealed. Sound metal with a localized problem does not need replacing. Our gutter repair guide walks through the middle tier.
The signs it is genuinely replacement
Once steel gutters rust through, or aluminum splits and cracks along the bottom, there is no cleaning or sealing that lasts. Water finds the next weak spot. This is the clearest tell.
Sectional gutters leak at the joints, and once several seams are going, resealing one just moves the drip to the next. Widespread seam failure is a system at the end of its life, not a repair.
Gutters sagging off the house usually mean the fascia behind them has rotted from years of overflow. New hangers will not hold in soft wood. That is fascia repair plus replacement, not a re-hang.
A run that dips in the middle and holds standing water has lost its pitch and often its structural line. If re-sloping does not hold because the metal is fatigued, it is replacement time.
Bubbling exterior paint, mildew streaks, or soft trim under the gutter line mean water has been getting behind it for a while. The gutter is no longer doing its one job.
Repairs are worth it once. When you are back at the same leak a second or third time, you are spending real money to postpone the inevitable. Replacement stops the cycle.
Why seamless, if you do replace
If the verdict is replacement, seamless aluminum is the sensible default around Sacramento: no seams to fail (the reason old gutters leak in the first place), no rust, a baked-on color, and a one-day install rolled to length on site. The full breakdown, including sizing for our atmospheric-river storms and honest cost ranges, is in the seamless installation guide.
The honest bottom line
Most gutters are a cleaning. A good number are a repair. Some are genuinely done. A straight installer will show you which one you are looking at and let the gutters make the case. If the "free inspection" jumps straight to a four-figure replacement without walking you through the metal, get a second opinion before you sign anything.