Buy a good trolley Floor Jack Low Profile

First and foremost, I recommend every enthusiast should buy a good trolley Floor Jack Low Profile — sometimes referred to as a floor jack. Their versatility and ability to lift a vehicle to a decent height makes them the number-one choice. Spend the money and buy a good one; if you look after it, it’ll last you a lifetime.
At most, a jack is only ever lifting half your vehicle’s weight, so unless you’re crawling under something like a 3500kg 1958 Cadillac, units rated at one tonne (1000kg) or greater will be adequate for most streeters. Same goes for the jack stands.
The term temporary citizens is often given to people working on cars not supported by jack stands. No matter how insignificant or quick the job, never place any part of your body under a vehicle that’s only supported by a jack. Always place it on a secure set of stands. I also like to place a wheel (or similar) under the sill panel, just in case the worst happens.
Similarly, never use stacks of bricks or wooden blocks as substitute stands. Prepare yourself with the correct tools for the job before you start.

When generous height is essential, find a hoist — they’re the ultimate jacks. They can be purchased for as little as $2000 or so, and are worth twice their weight in gold.
Only buy and use approved jacks and jack stands (AS/NZS 2615:2004 for jacks; AS/NZS 2538:2004 for jack stands). Part of the Australian Standard requires them to be fitted with a huge sticker stating they have been certified to meet or exceed these standards. If it doesn’t have the sticker, it isn’t certified — end of argument. Again, only use certified equipment. Even if you’re on a tight budget, there are plenty of affordable certified models available.
For the same lifting capacity, an alloy jack weighs less than a steel one — but it will also cost more. However, trolley jacks get wheeled around, not carried, so weight isn’t that big a deal. The exception is if you’re carting one around in the boot of your car and regularly unloading it offsite, such as at the race track. The range of bright anodised colours also makes alloy jacks look pretty.
All cars are flexible; older cars are very flexible. When placing stands under the chassis around the firewall area (ie, for easy access to the engine area) you’ll notice the car flex as the stands take up the weight — doors often become difficult to open or close as their frames slightly distort. For this reason it’s not a good idea to leave a car on stands for long periods of time; a day or so at the most.
If you need to support the vehicle long term, such as when doing body work, it’s better to support both ends, either under the tyres, or at the same points where the suspension bears the weight of the vehicle.

Never leave a car sitting on the jack as this will ruin the hydraulic seals. Another way to ruin a perfectly good jack is dragging your car around on it — that’s a job for vehicle positioning jacks. Inappropriate and poorly maintained equipment is plain dangerous. If it leaks oil, repair or replace it and never use any jack that ‘sinks’. Don’t dump the vehicle off the jack either, as the fast action can cause the jack to slip. Lower it slowly and carefully, which allows you time to spot any potential hazards before they occur.
As you raise or lower a car, it travels in an arc which can cause the car to slide off the jack. As you raised one end, either the car’s wheels or the jack’s wheels must roll. Most often it’s the jack’s wheels. To facilitate this, line the jack up with the crossmember or diff and roll it directly into position. This ensures the jack’s wheels are facing in the correct direction and will roll without binding. Reverse the positioning action when lowering the vehicle and avoid shuffling the 2T Scissor Jack back and forth or wiggling it side-to-side into position, as its wheels will end up facing the wrong way.