A gate motor rated for residential use will normally open and close up to 100,000 times or more in its life span if it has a light loading and it has been installed correctly. If being pushed to its maximum load limit or installation isn't ideal then it may last a lot less. An automatic gate for a single residence is likely to be used only a few times day or in extreme cases up to 18 times a day if there are quite a few people with vehicles that are busy. A gate operator that will last 100,000 open and close cycles in its life span will last 15 years if used 18 times a day on average so will be more than suitable. Although other factors can shorten the life span such as a gate being hit by a car causing shock forces on the operator, less than ideal installation, environmental effects such as salty or dusty air causing corrosion, insect penetration, lighting strike, flooding, tree roots in the ground or reactive ground causing the gate track (for sliding gates) or posts to move effecting the loading the gate operator must endure and other factors.

If a gate is being shared by more than one home or office this is a whole new ball game. If there's eight apartments or offices sharing one gate then its likely to get used on average something like 50 times a day, an operator rated for up to 100,000 open and close cycles in its life span will only last 5 years or so and will then need to be replaced. In this situation it would be better to use a motor that is engineered to last longer say 250,000 cycles, which would last 13 years or so. A motor with a longer life expectancy may be more expensive but not always and in the long run if it did would be better value for money and there wouldn't be the inconvenience of an operator starting to play up because its worn out, which can be frustrating.

Another factor is the amount of use a motor can take if used continuously with very little break between open and close cycles then it could start getting hot and cut out until it cools off, although generally 12V and 24V motors can take a lot more of this than a 240V single phase motor because they are more efficient and a 400V three-phase or a brush-less DC (BLDC) 12V/24V motor can handle continuous use without ever over heating because they are more efficient again. 

If there are up to 16 houses sharing a gate then a motor needs to be rated for up to 500,000 open and close cycles to get a reasonable life span. Any more than this then the motor should be rated higher than this. 12V and 24V DC motors that use brushes will need to have the brushes replaced every 100,000 to 200,000 cycles depending on how much the motor is loaded. Replacing brushes is part of the maintenance of this type of motor that gets a high amount of use. BLDC and Three-Phase motors don't have brushes so generally will last much longer before needing any maintenance.

How Maintenance Effects Life Span of a Gate Operator 

12V and 24V DC motors that use brushes will need to have the brushes replaced every 100,000 to 200,000 cycles depending on how much the motor is loaded even though other parts of an operator may be fine. Replacing brushes is part of the maintenance for an operator that gets a high amount of use. BLDC and Three-Phase motors don't have brushes so generally will last much longer before needing any maintenance although seals can deteriorate cause oil leaks, oil leaks can cause excessive wear of gearing and excessive loading on an operator can cause bearings to be flogged and get noisy. Replacing brushes, seals, lubricants, gears and bearings can prolong the life of a gate operator although the labour and parts required may be more than the operator is worth so is more likely to only be economic for higher value operators that get a lot of use. Small animals and insects can get into operators too and burn out electronic circuit boards along with lightning strikes, so measures to prevent this can extend the life of an operator too. 

Pushing a Gate Operator to its Maximum Load Limit

In the case of a sliding gate operator it is pushed to its limit if the gate is near the rated maximum weight for that operator on flat ground or if the gate is on a driveway slopes across, then its weight verses the amount of slope. 

With swing gates a gate operator that is pushed to its limit is one on a gate that is near the maximum rated width for that operator and has a constant high wind load on the gate or the gate is being lifted up a slope with rising hinges that then becomes width verses weight and slope. If a swing gate is at a rated maximum width for an operator but there is no wind or other loading then its not being pushed to its limit or if a gate is made from a material that allows wind to blow through or wind loading is only occasional then the operator isn't being pushed to its limit even if the gate is wider than the maximum rated for the operator.