1.1. Introduction to Economic Life

Today, we will discuss what economic life means in relation to machinery. Can anyone tell me what happens to the cost of a machine over time?

The costs might go up because of things like repairs or maintenance?

Exactly, Student_1! As a machine ages, we see increased operating costs, repair expenses, and potential downtime costs. This leads us to the concept of economic life — the period during which these costs are minimized.

Why is it important to know the economic life of a machine?

Good question, Student_2! Knowing the economic life helps businesses replace machines at the right time to avoid losses. If a machine costs more to maintain than to replace, it's a sign it's time to invest in a new one.

Can you give us an example?

Sure! We will later look at a track-mounted front shovel where we calculate its economic life, considering its purchase price, maintenance costs, and depreciation.

What do you mean by depreciation?

Depreciation is how much value a machine loses over time. It's an essential factor in cost calculations. Let's recap: economic life helps reduce costs by knowing when to replace machinery!

Now, let's dive deeper into the costs associated with machinery. What types of costs do you think increase as machines age?

Probably maintenance and repair costs?

And downtime costs, since the machine might break down more often.

Correct! Maintenance and repair costs tend to rise as the machine ages, leading to higher downtime and loss in productivity. These factors can significantly impact total machine costs.

What about obsolescence?

Excellent point, Student_3! Obsolescence occurs when a machine is no longer useful due to new technology or changes in market preferences. Both operational and obsolescence costs need to be factored in during replacement analysis.

How do we actually calculate these costs?

We will be using data inputs such as initial purchase price and annual increase due to inflation. We'll work through example calculations later.

Got it! So all these costs contribute to the decision-making process?

Absolutely! Understanding these costs will allow us to identify when it's most economical to replace a machine.

Let's apply our understanding with a specific example: calculating the economic life of a track-mounted front shovel. What do we need to start with?

We need to know the purchase price, right?

Exactly! The purchase price is 35,00,000. What other factors do we need?

Expected lifespan and depreciation method?

Correct! We'll use the double declining balance method for depreciation. We also consider the annual increase due to inflation, which is about 6%.

So, what’s our first step in calculations?

First, we calculate the depreciation for the first year using the formula: D = 2/n * BV. What value would we use for BV?

The initial purchase price?

Exactly! For the first year, the depreciation will be 8,75,000. Let's continue the calculations, and I'll show you how to find the new book value.

In assessing the economic life, how do we determine when to replace machinery?

By comparing the costs for replacement versus keeping the machine?

Exactly! We evaluate the cumulative costs over time. What factors do we include in those costs?

The purchase price increase and depreciation?

And the downtime costs as well!

Correct! For every year, we will calculate the replacement cost and track the cumulative costs to find the optimal replacement year. Can anyone tell me how we would summarize these findings?

By examining when the loss due to depreciation outweighs the savings from using the machine longer?

Exactly! Great understanding, everyone! It’s key to analyze these costs continuously.